SIP trunking connects an on-premise or self-cloud phone system (Asterisk, FreePBX, 3CX) to the Australian PSTN, giving it phone numbers and the ability to make and receive calls. Pricing is more complex than cloud phone system plans because there are more variables: per-channel fees, per-minute call rates versus unlimited bundles, DID number costs, and emergency calling fees. This guide breaks down current Australian SIP trunk pricing so you know what a fair price looks like and what to watch for in provider contracts.
How SIP Trunk Pricing Is Structured
A SIP trunk bill has three main components. Understanding each prevents surprises at invoice time.
1. Channel fees
Each SIP trunk channel supports one simultaneous call. A 4-channel trunk can handle 4 conversations at the same time. Channel fees are the base monthly cost, typically $4 to $10 per channel per month in Australia for standard plans. Some providers offer unlimited channels (metered on call volume rather than concurrency) but per-channel pricing is more common for SMB-scale deployments.
2. Call costs
Call costs cover the per-minute rates for each call type. Australian SIP trunk pricing distinguishes between:
- Local calls: Calls within the applicable local calling area or standard zone; sharing an Australian area code does not by itself make a call local. Some providers include these free; others charge 1 to 2 cents/minute.
- National calls: Calls to 02/03/07/08 numbers outside your local area. Typically free or 1 to 3 cents/minute.
- Mobile calls: Calls to 04xx numbers. This is where costs vary most significantly, from free (included in bundle) to 10+ cents/minute on metered plans. If your business makes frequent calls to mobiles, this line item matters.
- 1300/1800 calls: Calls to 1300 numbers (caller pays local rate) and 1800 numbers (toll-free). Connecting to 1300 numbers is typically free or very low cost; receiving calls on a 1300 DID has associated origination fees.
- International calls: Per-minute rates to international destinations. Rates vary by destination from 2 cents/minute (New Zealand, USA) to much higher for remote destinations.
3. DID number fees
DID (Direct Inward Dialling) numbers are the Australian phone numbers (02, 03, 07, 08 area codes, or 1300/1800) assigned to your SIP trunk for inbound calls. DID fees in Australia are typically $2 to $5 per number per month for geographic numbers. 1300 numbers cost $5 to $20 per month depending on the number and provider. If you port an existing number, the ported number usually takes on the same DID monthly fee.
Typical Australian SIP Trunk Plans
SIP Trunk Pricing Comparison. Australian Plans (April 2026)
| Budget metered | Mid-range unlimited | Business unlimited | |
|---|---|---|---|
| Channel fee | Check current provider rate | Check current provider rate | Check current provider rate |
| Local/national calls | 1-3c/min | Included | Included |
| Mobile calls (AU) | 8-12c/min | Included or 3-5c/min | Included |
| DID numbers | $2-4/month each | $2-4/month each | $3-5/month each (some included) |
| 1300 numbers | $5-15/month | $8-20/month | $8-20/month |
| Emergency calling (000) | Check: some charge $1-3/month | Usually included | Included |
| Minimum channels | 1 | 2-4 typical minimum | 4-8 typical minimum |
| Contract term | Month to month | Month to month or 12 months | Contract terms vary by provider and plan; month-to-month and fixed-term offers both exist. |
The key differentiator between budget and mid-range plans is mobile call inclusion. For a business that primarily calls landlines, a budget metered plan at $4 to $6 per channel plus call costs can be the cheapest option. An unlimited plan may cost less when mobile-call usage is high enough, but the result depends on actual minutes, PAYG rates, channel fees and fair-use conditions.
What a SIP Trunk Bill Looks Like: A Worked Example
A five-person accounting firm in Sydney with moderate call volume is a useful reference. For this illustrative example, assume peak demand of two to three concurrent calls and select four channels; an actual deployment should be sized from measured call data. At a mid-range Australian provider charging $7 per channel per month, channel fees are $28. Two Sydney DID numbers (02 area code) at $3 each add $6. Call costs depend on mobile call volume: businesses making mostly landline calls on a flat-rate plan add $15 to $25 per month in call costs. Full SIP trunk cost: $49 to $59 per month. Add a FreePBX or Asterisk VPS at $20 to $30 per month, and the complete self-hosted solution runs $69 to $89 per month for five staff.For comparison, a managed cloud phone system for the same five staff through an AU provider costs $25 to $45 per user per month, totalling $125 to $225 per month all-in -- including phone lines, hosting, and support. The SIP trunk approach is cheaper, but the gap is smaller than most expect once you factor in VPS hosting and the time cost of managing the system yourself. The economics at higher concurrency depend on the provider’s channel, usage and volume-pricing model; there is no universal ten-channel break point.How Many Channels Do You Need?
Channel count determines how many simultaneous calls your SIP trunk supports. As covered in our how many SIP trunks guide, the formula is based on peak concurrent call demand, not total users. A rough guide:
- These headcount ranges are only rough illustrations, size channels from measured peak concurrent calls, with appropriate allowance for growth and resilience, not from staff count alone.
Use our phone lines calculator to get a more precise figure for your business. Many SIP services are scalable, but confirm whether channel changes affect the plan, minimum spend or contract term.
Major Australian phone line providers
The Australian SIP trunk market has a mix of wholesale-focused carriers (minimum volume requirements, lower per-unit cost) and SMB-focused providers (no minimum, simple self-service portals).
Telnyx, A US-headquartered carrier with an Australian PoP in Sydney. Competitive per-channel pricing, pay-as-you-go model with no minimum commitment. Good for businesses that want a straightforward international carrier with AU presence. PJSIP-compatible, good Asterisk/FreePBX documentation.
Symbio Networks, Australian wholesale carrier, focused on resellers and higher-volume deployments. Symbio primarily positions these services for communications providers, wholesale customers and resellers; confirm eligibility and commercial minimums directly with Symbio. More appropriate for IT providers managing multiple clients than for single-business deployments.
VoIP.ms, Canadian provider with AU DID availability. Popular with FreePBX users due to competitive pricing and comprehensive documentation. VoIP.ms operates a Sydney POP as well as overseas servers; organisations with data-sovereignty requirements should verify where signalling, media, account data and records are stored or processed.
Australian-based providers: Several smaller Australian carriers offer SIP trunking for SMBs. Pricing, support location and data residency vary by provider and should be verified separately rather than inferred from the provider’s headquarters. Evaluate on a case-by-case basis, the market is fragmented and pricing varies significantly.
Before committing to any AU SIP trunk provider, confirm three things: whether 000 emergency calling registration is included at no extra cost (not all providers include it), whether a test period is available before you commit to a contract term, and what the minimum monthly spend is. Some providers impose minimum monthly charges or minimum total costs. Check the provider’s current CIS or service terms for the amount and how it applies.Hidden Costs to Watch For
Emergency calling (000) fees: Some providers charge a monthly per-trunk or per-DID fee for 000 emergency call capability. This is not universal, some providers include it, others charge $1 to $3 per month per DID. Confirm whether 000 is supported and at what cost before signing up. Legally, your business phone system must support 000 calls. See our NBN VOIP guide for the 000 obligation details.
Number porting fees: Porting fees vary by provider, number type and port complexity; simple ports may be free, while complex or range ports can cost substantially more than $50. Some providers charge a porting fee per number; others include it. Get this in writing before you start the process.
Inbound origination fees: Inbound charging varies by provider: it may be included, metered per minute or covered through paid inbound channels. Confirm the applicable model and whether inbound calls consume your purchased concurrency.
CODEC transcoding fees: Some wholesale carriers charge extra if your PBX requests a codec that requires transcoding (e.g. you request G.729 but the trunk delivers G.711 and the carrier transcodes). Confirm supported codecs and any transcoding charges with the provider; using a codec supported end-to-end can avoid transcoding.
Minimum usage fees: Some providers have a minimum monthly spend (e.g. $20/month minimum). On low-volume trunks, the minimum can exceed your actual usage cost. For businesses with very low call volumes, confirm whether the minimum applies.
SIP ALG (Session Initiation Protocol Application Layer Gateway) deserves specific attention. It is a feature built into most consumer and small-business routers that attempts to assist SIP traffic passing through NAT. In practice, SIP ALG on common NBN routers rewrites SIP packet headers incorrectly and causes symptoms including calls dropping mid-conversation, inbound calls routing directly to voicemail, and one-way audio where one party cannot be heard. If your SIP trunk has intermittent issues that cannot be explained by overall network quality, disabling SIP ALG in your router administration panel is the first diagnostic step. PBX vendors such as 3CX commonly recommend disabling SIP ALG, but follow the documentation for your PBX, router and trunk provider.SIP Trunk vs cloud phone system: Total Cost Compared
A SIP trunk is only one part of the cost for a self-cloud phone system deployment. The full cost of a self-hosted SIP trunk setup includes:
- PBX software licensing (FreePBX core software is free; 3CX is priced annually per system by simultaneous-call tier, so check its current official price table)
- Server or VPS costs vary with PBX requirements, capacity, redundancy, backups and support.
- SIP trunk fees (channels + call costs + DID fees)
- IT management time
Compare this to a fully managed cloud phone system at $30 to $55 per user per month. For smaller teams, managed cloud service may have a lower total cost once support labour is included, but there is no universal 15-user threshold; compare both options using the same usage and support assumptions. For 20+ users with in-house IT capability, self-hosting with SIP trunks can be meaningfully cheaper. Run the numbers for your specific scale before deciding. See our SIP trunk vs cloud phone system cost comparison.
SIP trunk pricing is one component of a broader cost comparison between self-hosted PBX plus SIP trunks and fully managed cloud phone systems. Our guide to the best phone system for small business in Australia covers this cost comparison in detail and identifies the team sizes where separate SIP trunks and self-hosted PBX come out ahead of managed cloud.
If you are still weighing up whether to move to internet-based calling at all, our guide to cloud phone systems vs traditional phones for Australian businesses covers the full comparison including cost, reliability on NBN, and the practical considerations for Australian businesses making this switch.
What Most Businesses Get Wrong With SIP Trunks
Over-provisioning channels at sign-up. Some businesses may over-provision channels by sizing to headcount rather than measured peak concurrency. A five-person business should size channels from measured peak concurrent calls rather than assume a fixed maximum. Start with two or three, monitor peak usage in the first billing cycle, then scale. SIP trunk channels are elastic in most AU provider plans.
Not confirming 000 support before going live. For a service using a public number, the carriage service provider must supply the customer’s service-address information to the Integrated Public Number Database (IPND) and keep it current. Carriage service providers supplying an emergency telephone service are generally required to give end users access to 000 and carry emergency calls, subject to the Determination’s scope and exceptions; the customer PBX must also be configured so it does not block that access. Confirm 000 registration is included, in writing, before porting any numbers.
Treating the trunk fee as the total cost. The complete picture includes VPS hosting ($20 to $60 per month), PBX software licensing (3CX, FreePBX, or Asterisk), firewall configuration time, and ongoing maintenance. For teams under 15 users, a fully managed cloud phone system often costs less once the full comparison is run. See our SIP trunk vs hosted PBX comparison for the full cost breakdown by team size.
Your Next Steps
Before committing to a SIP trunk provider:
- Measure your peak concurrent call volume over a typical week, not headcount, before ordering channels
- Confirm 000 emergency calling registration is included and not a separate add-on
- Ask each provider how it records and updates your service address in the IPND, and get confirmation in writing
- Get a full quote including DID fees, minimum monthly spend, and any codec or transcoding charges
- Run the total cost comparison (trunk + VPS + PBX licensing + maintenance time) against a managed cloud quote before making a decision
What is a fair price for SIP trunking in Australia?
Can I use a SIP trunk with any PBX?
Do I need to pay for each phone number separately?
Is there a minimum number of SIP trunk channels?
Does a SIP trunk support 000 emergency calls?
Related reading:
- SIP trunk vs cloud phone system
- How many SIP trunks do I need?
- phone line providers in Australia
- FreePBX setup guide
Not sure whether SIP trunking or a managed cloud phone system is right for your business? Tell us your setup and we will give you a straight answer.
Get a RecommendationEvery SIP trunk setup has different costs depending on call volume, channel count, and provider. A small 3CX installation with 5 channels costs very differently from a setup handling 50 simultaneous calls. Tell us your setup details and we'll give you a specific cost estimate. We reply personally. Not a bot, not a form letter.
Every business is different. Tell us your setup and what you are trying to achieve. We reply personally. Not a bot, not a form letter.
Ask a Question