SIP Trunk Providers Australia Compared (2026)

This guide covers SIP trunk providers in the Australian market for businesses running their own on-premise or self-hosted PBX. It includes independent pricing comparisons, an honest assessment of the major providers, and a clear explanation of when SIP trunking is the right choice versus a fully hosted VOIP service. By the end, you'll know which provider suits your call volume and setup, and what contract terms to watch for.

SIP Trunking vs Hosted VOIP: Which Do You Need?

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

Hosted VOIP (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 VOIP providers 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 SIP trunk 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.

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 set of credentials (a SIP username, password, and server address) that you configure into your PBX. When someone calls your business number, the call arrives at your SIP trunk provider, who routes it over the internet to your PBX, which then rings the right phone. Outbound calls reverse that path.

A single SIP trunk can carry one call at a time. If you need 4 simultaneous calls, you need 4 channels. Providers sell channels as the unit of capacity, either on a per-channel monthly fee or bundled as part of a plan. You also need at least one DID (Direct Inward Dialling) number per channel, which is the actual phone number callers dial. 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. Australian telecommunications regulations require that VOIP services support 000 emergency calling. For SIP trunk providers, this means they must be able to route calls to the Triple Zero network and, where possible, pass 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 SIP trunk provider must support number porting from your current carrier. Porting in Australia is managed through the ACMA's number portability framework. Standard porting takes 5-10 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. G.711 is uncompressed and the highest quality but uses the most bandwidth (~87kbps per call). G.729 is compressed (~8kbps per call) and used on low-bandwidth connections. G.722 is wideband HD audio. Your PBX and your phones need to support the same codecs as your SIP trunk 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. Tier 1 providers have dual PoP (two geographically separate infrastructure nodes) so that if one fails, calls automatically failover to the second. 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 SIP trunk 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 VOIP provider offering both hosted PBX (cloud phone system) 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 (MNF Group)

MyNetFone is one of the longer-established Australian VOIP carriers, now part of the MNF Group. It operates its own AU network infrastructure with multiple points of presence, making it a solid choice for businesses requiring redundancy and AU-based routing. MNF Group carries a significant portion of Australia's wholesale voice traffic, which means the network quality is generally high and the 000 routing is well-established.

The trade-off is support responsiveness. MNF Group operates at scale, and support for small SIP trunk customers can feel less personalised than a specialist like Maxotel. Pricing is competitive, and the portal is functional for managing channels and DIDs. Best suited to: businesses with in-house IT capability who want AU-native infrastructure and are comfortable with self-service management.

Aussie Broadband

Aussie Broadband is primarily an Australian ISP that has expanded into VOIP services including SIP trunking. Its main advantage is bundling: if your business NBN is already with Aussie Broadband, adding SIP trunks from the same provider simplifies billing and may reduce the risk of ISP-level interference with VOIP traffic (some ISPs de-prioritise third-party VOIP). AU infrastructure, good network quality, and a provider with a strong reputation for customer service in the NBN market.

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, often at lower per-channel and per-minute rates than AU-native providers. 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. Neither has infrastructure in Australia, which means call audio is routed offshore, adding latency. More critically, their 000 emergency call support for Australian numbers is limited or uncertain. 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:

These figures assume an unlimited local and national call plan. Per-minute pricing can be significantly cheaper for very low-volume deployments. For a business making 200 minutes of calls per month across 2 channels, per-minute pricing at $0.03/min works out to $6 in call costs, making total monthly spend around $20-25. At that volume, per-minute beats unlimited plans. For 2,000+ minutes per month, unlimited plans save money.

DID numbers (the actual phone numbers) are typically charged separately at $2-5 per number per month. You need at least one DID per inbound number your business uses. If you want to keep your existing numbers, that's a porting fee (often a one-off $20-50 per number) plus the ongoing DID cost at your new provider.

Hosted VOIP 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, hosted VOIP is significantly simpler.

What's your team size? For 1-15 seats, hosted VOIP typically works out cheaper than on-premise PBX plus SIP trunks when you factor in server hardware, licencing, and ongoing IT time. From 20-30 seats upward, the economics can shift in favour of on-premise, particularly if you have in-house IT.

Do you need deep customisation? On-premise PBX with SIP trunks gives you more configuration control than hosted VOIP, 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, hosted VOIP covers everything they actually need.

Contract Traps to Watch For

Long minimum contract terms. Some SIP trunk 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 $500-2,000 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. Under Australian Consumer Law, providers cannot make it unreasonably difficult to port numbers, but fees for the process itself are permitted.

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. The contract should explicitly state that the provider supports 000 emergency calling and that your service address is registered. This is a legal requirement under the ACMA's carrier obligations. 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

Most reputable Australian SIP trunk providers offer a trial period or trial account. 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. Call 000 from your new SIP trunk connection. Confirm you reach the emergency operator and that they can see your registered service address. This is not optional.

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

PSTN copper is gone. Australia completed its copper network migration in 2025. All 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 and FTTC connections are the most reliable for business VOIP. 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. This applies regardless of which provider you use.

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 SIP trunk provider should be able to advise on the correct port range to prioritise.

Number porting timelines. Porting an Australian phone number from one carrier to a SIP trunk provider typically takes 5-10 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 without Australian infrastructure. The lower per-minute rates offered by international SIP trunk providers are attractive until you experience the call quality from offshore-routed audio. AU-based businesses need AU-based infrastructure. The $5-10/month saving per channel is not worth degraded call quality and uncertain 000 support.

Mistake 2: Not registering a service address for 000. Some businesses set up SIP trunks and never complete the 000 location registration with their provider. This is a legal obligation and a safety risk. When you sign up with a SIP trunk 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, most 10-person businesses rarely have more than 3-4 simultaneous calls. 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 SIP trunk provider, work through this checklist:

• Confirm you actually need SIP trunks, not hosted VOIP. If you don't have a PBX already, start with hosted VOIP 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 the trial period to test call quality, 000, and concurrent calls before committing.
• Read the minimum contract term and exit terms before signing.
• If you're not sure about setup, a specialist VOIP provider can often help configure SIP trunks into your existing PBX as a service.