SIP Trunk Providers Australia Compared (2026)

SIP Trunking vs Cloud Phone System: Which Do You Need?

This distinction matters before you read any further. SIP trunking is not the same as a cloud phone system. Understanding which you need will save you from buying the wrong product entirely.

A cloud phone system (also called hosted PBX or cloud PBX) is a complete phone system delivered as a service. The provider supplies the PBX software, the call routing, the number, and the connection to the phone network. You add phones and they work. Maxotel, Vonex, and similar providers offer this. Most Australian small businesses with 1-30 seats should start here. See our guide to the best business phone companies for small business in Australia.

SIP trunking is just the connection layer. It's the virtual phone line between your own PBX and the PSTN (the broader phone network). You own and run the PBX software yourself. The phone line provider gives you channels (simultaneous call capacity) and phone numbers, and carries your calls to and from the public network. You configure the SIP trunk credentials into your PBX manually.

Bundled or bring your own trunk. Cloud phone system companies sell in two ways. A bundled service includes the connection to the phone network, so there is no separate SIP trunk to manage, but you usually cannot swap in a cheaper third-party trunk later because the carrier part is built into the product. An unbundled setup pairs PBX software you run or rent (3CX, FreePBX or Asterisk) with a SIP trunk from a provider you choose. That gives you carrier choice, at the cost of two vendors to deal with when something goes wrong. If carrier flexibility matters to you, choose the unbundled model from the start.

What SIP Trunking Actually Is

A SIP trunk is a virtual telephone line delivered over your internet connection. Instead of a physical copper PSTN line into your office, a SIP trunk is a connection you configure into your PBX, usually with a SIP username, password and server address (some providers authenticate by your static IP address instead). When someone calls your business number, the call arrives at your phone line provider, who routes it over the internet to your PBX, which then rings the right phone. Outbound calls reverse that path.

A SIP trunk can carry multiple concurrent calls. Providers commonly express capacity as channels, with each channel supporting one simultaneous call, so if you need 4 simultaneous calls, you need 4 channels, sold on a per-channel monthly fee or bundled as part of a plan. DID (Direct Inward Dialling) count is independent of channel count: obtain a DID for each inbound number you need, not one per channel. For a full technical explanation, see our guide to SIP trunking explained for Australian businesses.

Key Things to Evaluate When Choosing an Australian SIP Trunk Provider

Australian point of presence (PoP). This is the most important technical factor. A PoP in Australia means your call audio travels a short physical distance between your PBX and the provider's infrastructure. Providers using overseas PoPs (US or Singapore-routed) introduce latency that degrades call quality. For business calls, you want under 50ms round-trip latency. Australian PoP is close to mandatory for a quality experience.

000 emergency call support. Not every VOIP service can call 000: ACMA says you can call 000 from any fixed or mobile phone and certain VoIP services. A provider that supports it routes your calls to the Triple Zero service and, where possible, passes location information. Confirm this before signing up. Some smaller or international providers have limited or no 000 support for Australian numbers.

Number porting. If your business has existing phone numbers you want to keep, the phone line provider must support number porting from your current carrier. Porting in Australia is managed through the ACMA's number portability framework. Individual local-number ports generally take 8 to 15 business days; complex ports may take up to 30 business days. Some providers are better than others at managing the process without service interruption. Ask about their porting track record before committing.

Pricing model. There are two main models. Per-channel plus per-minute: you pay a monthly fee per simultaneous call capacity, plus a rate per call minute. Unlimited plans: a flat monthly fee per channel that includes a call allowance (usually unlimited local and national calls, with international charged separately). For businesses with predictable moderate call volume, unlimited plans offer cost certainty. For low-volume deployments, per-minute can be cheaper.

Codec support. Codecs determine how voice is compressed for transmission. In Cisco's 20 ms Ethernet example, G.711 has a 64 kbps codec rate and uses about 87.2 kbps on the wire, while G.729 has an 8 kbps codec rate but uses about 31.2 kbps on the wire. G.722 is a 7 kHz wideband codec operating at 48, 56 or 64 kbps. Your PBX and your phones need to support the same codecs as your phone line provider. Most modern providers support G.711, G.722, and G.729. If you need T.38 for fax over IP, confirm support explicitly.

Redundancy and uptime SLA. Redundancy arrangements vary by provider and may depend on customer-side DNS, SBC or PBX configuration. This is worth asking about if your business depends on phone availability. An uptime SLA of 99.9% sounds good but translates to 8.7 hours downtime per year. 99.99% is about 52 minutes. Understand what the SLA covers and what compensation applies for outages.

Static IP requirement. Some phone line providers require your PBX to have a static public IP address for authentication. Others use IP whitelisting, username/password authentication, or registration-based authentication that works with dynamic IPs. If your business internet connection has a dynamic IP, check whether the provider supports registration-based auth or IP-less authentication before signing up.

Australian SIP Trunk Providers Compared

Provider Profiles

Maxotel

Maxotel is an Australian specialist business phone company offering both cloud phone systems (hosted PBX) and SIP trunking. For businesses running their own PBX, Maxotel's SIP trunk service delivers AU-based infrastructure, good call quality, and the kind of support response you get from a specialist rather than a large ISP. Their primary focus is the SMB market, which means their onboarding and support processes are built around businesses that don't have dedicated telecoms engineers.

Maxotel SIP trunks support 3CX and FreePBX deployments, with setup documentation available. They carry Australian DID numbers including metropolitan and regional areas, and 1300/1800 numbers where required. Number porting is supported with reasonable timelines. Local AU support is a consistent differentiator versus larger ISP-based providers. Best suited to: SMB deployments of 1-50 seats using 3CX or FreePBX who want a local provider with genuine support responsiveness.

MyNetFone (now Symbio)

MyNetFone was MNF Group's small-business and residential voice brand. The former MNF Group renamed itself Symbio, and the MyNetFone website now redirects to Symbio, which sells SIP trunking, Teams calling and number services to enterprises, government and service providers rather than publishing small-business plans. That is why MyNetFone no longer appears in the comparison table above.

If you are an existing MyNetFone customer, check your latest bill to see which company now supplies your service before comparing plans. A small business buying a new SIP trunk will find the providers above, which publish their prices, the more practical shortlist.

Aussie Broadband

Aussie Broadband is primarily an Australian ISP that has expanded into VOIP services including SIP trunking. Its SIP trunks require an active Aussie Broadband NBN service, so they suit businesses whose NBN is already there: one provider and one bill, AU infrastructure, and a strong reputation for customer service in the NBN market. The service is month-to-month with no exit fee.

SIP trunking is not their primary product, so the SIP-specific feature depth is less than a pure-play VOIP carrier. Best suited to: businesses already using Aussie Broadband for their NBN connection who want the simplicity of a single provider and are running a straightforward SIP trunk deployment.

Telnyx and VoIP.ms: International Providers

Telnyx (US-based) and VoIP.ms (Canadian) both offer Australian DID numbers and serve AU customers. Both bill per minute in US dollars with no channel fee. The appeal is price and feature richness, particularly for technically capable operators who want programmatic API control over their trunking setup.

The limitations for Australian business use are significant. Telnyx and VoIP.ms both operate Sydney points of presence, so Australian traffic does not necessarily have to be routed offshore. Telnyx documents support for Australian 000 and IPND address handling. VoIP.ms also states that Australian national routing includes emergency service; confirm each provider's current setup and address-registration requirements before deployment. Australian telecommunications regulations require 000 to be accessible. Using a provider that cannot reliably route 000 calls from your Australian business numbers is a compliance and safety risk. These providers are better suited to developers and international businesses using AU numbers programmatically, not as a primary business phone system carrier.

What You Should Actually Expect to Pay

A realistic cost model for an Australian SIP trunk deployment looks like this:

To work out a monthly figure, multiply the provider's per-channel price by the channels you need. On the calls-included plans in the provider table above, a channel cost from $27 (Pennytel) to $60 (Aussie Broadband) a month when checked in October 2026. Pay-as-you-go plans have a much lower line fee and charge for each call instead, typically 10c to 15c per local or national call, so they suit low call volumes: 100 local calls a month adds about $10 to $15 ($0.10-0.15 x 100) to the line fee. Busy lines are cheaper on a calls-included plan.

DID numbers (the actual phone numbers) are often charged separately: $0.50 a month at Pennytel, and $2 a month for extra numbers at Maxotel and Vonex, which each include one or more numbers with the plan. You need at least one DID per inbound number your business uses. If you want to keep your existing numbers, there is usually a one-off porting fee per number ($30 at Vonex; $25 to $330 at Pennytel depending on complexity) plus the ongoing DID cost at your new provider.

Cloud Phone System vs SIP Trunking: Which Is Right for Your Business?

Work through these questions to identify which approach suits your situation:

Do you already have a PBX running? If yes, SIP trunking is almost certainly what you need. If no, start with the next question.

Do you have the technical capability to configure and maintain a PBX? Running 3CX or FreePBX requires someone who can set up SIP trunks, configure ring groups, manage extensions, and troubleshoot when calls don't work. If that's you or someone on your team, on-premise PBX plus SIP trunks is a viable path. If not, a cloud phone system is significantly simpler.

What's your team size? Whether a cloud phone system or an on-premise PBX with SIP trunks is more cost-effective depends on factors such as hardware, licensing, support, usage, channel requirements, included-call terms and ongoing IT time; on-premise options may be more economical in some circumstances, particularly if you have in-house IT.

Do you need deep customisation? On-premise PBX with SIP trunks gives you more configuration control than a cloud phone system, including custom dialplans, complex call routing logic, and integration with on-premise systems. If your business has genuinely complex telephony requirements, this matters. For most SMBs, a cloud phone system covers everything they actually need.

Contract Traps to Watch For

Long minimum contract terms. Some phone line providers, particularly larger telcos, lock you into 12-24 month contracts with early termination fees. For most SMBs, month-to-month or 3-month minimum terms are preferable. You want the ability to switch if quality or support degrades without facing a large exit fee. Always ask about minimum term and exit costs before signing.

Porting fees embedded in the contract. Some providers charge a porting fee to move your numbers away when you leave. This fee should be disclosed upfront. Check the contract for any number release or porting-out fees before signing. Number-porting obligations arise under the Telecommunications Numbering Plan 2025 and registered portability codes. Porting fees may apply; ACMA advises customers to dispute unreasonable charges with the provider and then the TIO if necessary.

Channel minimums. Some providers require a minimum number of channels (often 4-5) even if you only need 2. This can push monthly cost significantly above what you actually need. Confirm the minimum channel count and whether you can scale down if your call volume turns out to be lower than projected.

Unclear 000 obligations. Ask the provider to confirm in writing that the service supports 000 emergency calling and that your service address is recorded in the Integrated Public Number Database (IPND). If the contract is vague about 000 support, ask in writing before signing.

Bundled number porting with service start. Some providers start billing from contract signature, not from the date your numbers are ported and your service is live. If porting takes 10 business days, you may be paying for two services simultaneously. Clarify billing start date relative to service activation.

How to Test a SIP Trunk Provider Before Committing

Some Australian phone line providers offer a trial period or trial account. If yours does, use it. Here's what to test before you commit:

Call quality in both directions. Make a call out and receive a call in. Listen for echo, jitter (choppy audio), or one-way audio. If you hear any of these, run a network quality test first to isolate whether the problem is your connection or the provider. Good quality on both ends is the baseline.

000 test. Do not place a non-emergency test call to 000. Confirm emergency-call routing and the registered IPND address with the provider, and only make a test call under an authorised test procedure.

Concurrent call test. Make two simultaneous calls to confirm your channel count is working as expected. If you've provisioned 4 channels, test 4 concurrent calls and confirm the 5th is rejected or queued correctly.

Codec negotiation. Confirm your PBX and the SIP trunk are agreeing on the codec you expect. Most PBX platforms log the negotiated codec for each call. If you're expecting G.722 HD audio but calls are falling back to G.711, check your PBX codec priority settings.

Support response time. Contact support during the trial with a non-urgent question. How long does it take to respond? Is the response helpful? This tells you what to expect when something actually goes wrong.

Australian Reality: What You Need to Know

Australia has not completed copper migration. NBN reported in 2026 that approximately 622,000 FTTN premises remained in its legacy-copper upgrade program, with eligible upgrades continuing through 2030; Telstra also continues to offer some copper PSTN voice services. Most business phone calls now run over IP connections. SIP trunking is how businesses with their own PBX connect to the broader phone network. There is no longer a PSTN-based alternative for new or migrating services.

NBN quality affects SIP trunk performance. Your SIP trunk is only as good as your internet connection. FTTP is generally more reliable than copper-based NBN technologies. Both FTTN and FTTC retain copper segments, and NBN says FTTC has higher fault rates than its other copper-based networks. FTTN introduces copper in the last mile and adds variability. If your business is on FTTN and experiencing call quality issues with your SIP trunk, the NBN connection type is the first thing to investigate, not the trunk provider. See our VOIP cost guide for a breakdown of NBN connection types and their impact on call quality.

SIP ALG: turn it off. Many business-grade routers have a feature called SIP ALG (Application Layer Gateway) that is supposed to help with VOIP but almost universally causes problems. Symptoms include one-way audio, dropped calls, and registration failures. The first configuration step for any new SIP trunk deployment in Australia is to disable SIP ALG in your router settings. Unless your provider or PBX vendor says otherwise, do this whichever provider you use.

Carrier Grade NAT (CGN). Some NBN plans use CGN, where several customers share one public IP address. CGN can interfere with SIP signalling and cause trunk registration drops or one-way audio. Whether it applies depends on your internet provider and plan. If you see those symptoms, ask your internet provider whether your service uses CGN and whether a public or static IP is available, then check your firewall, port mapping and SIP ALG settings. A cloud phone system can reduce this complexity, but its phones still run over your NBN connection and firewall, so local network conditions still matter.

QoS (Quality of Service). If your business runs voice and data on the same internet connection, configure QoS on your router to prioritise voice traffic (typically UDP on ports 5060 and the RTP range your provider specifies). Without QoS, a large file download or video stream can compete with a phone call for bandwidth, causing audio degradation. Most modern business routers support QoS configuration. Your phone line provider should be able to advise on the correct port range to prioritise.

Number porting timelines. Porting an individual Australian geographic number from one carrier to a phone line provider generally takes 8 to 15 business days; a complex port may take up to 30 business days. 1300 numbers and fax numbers have their own porting processes. During the porting period, your existing service remains active. On completion, calls route to the new provider. Porting failures do occur, usually caused by mismatched account details between the gaining and losing carrier. Provide exact matching account details to avoid delays. See our guide to business phone systems in Australia for more on the porting process.

What Most Businesses Get Wrong with SIP Trunking

Mistake 1: Choosing a provider on headline call rates alone. International providers such as Telnyx and VoIP.ms bill per minute in US dollars with no channel fee, which can look cheap, and both now run Sydney points of presence. What matters more for an Australian business line is 000 handling, emergency address registration, porting support for Australian numbers, and support during Australian business hours. Confirm all four before comparing price.

Mistake 2: Not registering a service address for 000. Give your provider an accurate service address and update it when you move. The carriage service provider is responsible for supplying correct customer and service information to the IPND. When you sign up with a phone line provider, confirm they have your correct service address registered for emergency call routing. If you move premises, update your address with the provider immediately.

Mistake 3: Over-provisioning channels. A common error is buying more channels than you need because it feels safer. For a 10-person business, it's tempting to buy 10 channels. In practice, simultaneous call volume varies substantially by industry and calling patterns. Over-provisioning adds cost with no benefit. Start with a realistic assessment of your peak simultaneous call volume, add one buffer channel, and scale up if needed. Most providers allow easy channel additions.

Your Next Steps

Before you sign with a phone line provider, work through this checklist:

• Confirm you actually need SIP trunks, not a cloud phone system. If you don't have a PBX already, start with a cloud phone system first.
• Identify your peak simultaneous call volume. This determines how many channels you need. When in doubt, start with 2-3 and scale up.
• Confirm the provider has Australian infrastructure (AU PoP) and verified 000 support.
• Check their number porting process if you're bringing existing numbers.
• Disable SIP ALG on your router before testing.
• Use any trial period to test call quality and concurrent calls before committing. Do not place a test call to 000; confirm emergency-call routing and the registered IPND address with the provider instead.
• Read the minimum contract term and exit terms before signing.
• If you're not sure about setup, a specialist business phone company can often help configure SIP trunks into your existing PBX as a service.

SIP trunk providers vary significantly on international call rates, which matters for businesses that call suppliers, clients, or partners in the UK, US, NZ, or Asia regularly. For a breakdown of how international calling is structured on AU VOIP and SIP trunk plans, including which countries are typically bundled and which attract per-minute charges, see our guide to international calls on a VOIP system in Australia.

Every SIP trunk setup is different. The right provider for a 3CX installation is not the same as for a FreePBX box with high call volume. Tell us your PBX platform, your monthly call volume, and whether you need Australian geographic numbers. We'll give you a specific recommendation. We reply personally. Not a bot, not a form letter.