Cambodia Business Visa Extensions for Australians: 2026 In-Country Guide (1, 3, 6, 12 Months)

When to start the extension paperwork

Two weeks before your initial 30 days expire is the minimum. Three weeks is safer. The reason is agent turnaround: the standard 7–14 business days is a range, not a promise, and the upper end happens often enough that you do not want to be inside that window when your visa runs out. Most Aussies who get caught short tried to start the paperwork in the last week of their 30-day stay, then discovered the agent's quoted 10 business days lined up exactly with their expiry date, with no margin if anything slips.

Lodge early and you keep all the levers. If the extension comes back faster than quoted, you have peace of mind earlier. If it runs slow, you are still safely inside your original 30-day stay while the agent finishes the job. There is no penalty for starting two or three weeks out — the extension stamp dates from when Immigration approves it, not from when you handed in the paperwork, so you do not lose any days by being early.

Now the part Aussies misjudge: the overstay penalty. If your initial 30 days lapse before the extension is back, you are technically overstaying. The penalty is approximately $10 USD per day, paid in cash at the airport on exit — and the overstay is noted on your Cambodian immigration record. A few days is mostly an inconvenience and a cash fine. A few weeks can affect future Cambodia visa applications and is worth avoiding by simply starting the paperwork on time.

Picking an immigration agent in Phnom Penh or Siem Reap

Most Phnom Penh and Siem Reap immigration agents handle Aussie extensions routinely. The job is paper-pushing — the agent's job is to know the current Immigration counter, the current paperwork format, and the right hands to hand your passport to. There are dozens of competent ones, and a smaller number that you should walk past. The signal-to-noise question is what to look for, and what to walk away from.

Look for: a published price list (not 'ask us for a quote' — agents that hide prices tend to flex them based on what they think you can pay); reasonable turnaround quotes in the 7–14 business day range (anyone promising 'tomorrow' or '24 hours' is either lying or about to do something irregular with your passport); willingness to hold your passport for the full duration with a written receipt; and a physical office you can walk into, not just a Telegram handle.

Walk away from: agents who want to keep your passport without a receipt; agents quoting wildly below market (the 1-month for $30 USD agent is the one whose extension stamp Immigration questions at the airport); agents pushing 12-month multi-entry as the only option regardless of what you need; and any agent who asks for the full fee in cash up front before they have even sighted your passport.

We keep a curated shortlist of agents in Phnom Penh and Siem Reap who routinely process Aussie extensions cleanly — the list is small, vetted, and updated quarterly. Email our support desk for the current names. For context on how Australia's official travel advice frames in-country administrative steps generally, the Smartraveller advisory is worth a quick read before you fly.

Single-entry vs multi-entry: the practical Aussie choice

The choice between single-entry and multi-entry comes down to one honest question: will you leave Cambodia during the extension? If the answer is no — you are staying put in Phnom Penh, you have no plans to weekend in Bangkok, you are not flying home for a wedding — single-entry is fine and saves you the multi-entry premium of roughly $30–50 USD.

If the answer is yes, or even maybe, multi-entry is the right pick. Re-entering Cambodia on a single-entry extension means the extension is burnt the moment you cross the border outbound — you cannot use it to come back in. To re-enter you would need to buy a fresh Business eVisa at $90 USD (~$137 AUD), wait the three business days for approval, and start a new 30-day clock. Compared with that, the multi-entry premium is a bargain on the first trip out.

The common Aussie scenarios where multi-entry pays for itself: a digital nomad popping to Bali for a friend's wedding; a consultant flying back to Sydney mid-project for a partner meeting; a long-stay traveller doing a weekend in Ho Chi Minh City or Bangkok purely for the change of scene. If your trip will touch Vietnam at any point, the Vietnam-Cambodia visa combo guide for Australians covers the back-and-forth side of the route.

Real Aussie extension scenarios — three worked examples

Here are three honest worked scenarios from the three most common Aussie extension cases we see. Numbers are 2026 indicative pricing — the Business eVisa is $90 USD (~$137 AUD) all-in through us, the extension fees are mid-range agent quotes in Phnom Penh.

Scenario one — Sydney consultant on a 90-day Phnom Penh project. Enters on the Business eVisa, lands at Phnom Penh, has client meetings booked through to day 85. Two weeks into the stay, she visits an agent and lodges a 3-month single-entry extension at $120 USD. Total visa cost across the whole project: $90 USD initial + $120 USD extension = $210 USD (~$320 AUD), all in. She finishes the project, exits Cambodia on day 89, no overstay, no drama.

Scenario two — Melbourne digital nomad doing a 6-month wet-season trial in Siem Reap. Enters on the Business eVisa, settles into an apartment near Wat Damnak, decides in week two that she wants to pop back to Bali for a long weekend halfway through. Lodges a 6-month multi-entry extension at $230 USD ($200 USD base + $30 USD multi-entry premium). Total: $90 USD initial + $230 USD extension = $320 USD (~$487 AUD). She uses the multi-entry for the Bali trip in month three, comes back in cleanly, finishes the six months.

Scenario three — Brisbane retiree couple on a 12-month Kampot reconnaissance. They want to live through both wet and dry seasons before deciding whether to relocate properly. Enter on the Business eVisa each, lodge 12-month single-entry extensions at $350 USD each. Per traveller: $90 USD initial + $350 USD extension = $440 USD (~$670 AUD) for a year-plus of legal stay. No leaving Cambodia planned, so the multi-entry premium would have been wasted money — the single-entry is the correct call for their use case.

Pulling it together for your 2026 extended Cambodia stay

The summary for Aussies: only the Business eVisa extends in-country, lengths are 1/3/6/12 months, extensions go through an agent in Phnom Penh or Siem Reap, allow 7–14 business days, start two weeks before your initial 30 days expire, pick multi-entry if there is any chance you will leave Cambodia. If you have not yet sorted the underlying visa, the Cambodia Business eVisa application is the place to start, and the Australia country pillar covers permanent residents, dual citizens, and the wider edge cases.

For the cost side mapped across the whole journey — initial visa, extension, the e-Arrival Card — the Cambodia visa cost guide for Australians has the full breakdown. If your trip is timing-sensitive, the Cambodia visa processing time from Australia piece covers the upfront 3-business-day window and how to plan around Cambodian public holidays. And if you are still weighing the Tourist option against the Business one, the Cambodia Tourist visa for Australians and Cambodia eVisa vs Visa on Arrival comparisons sit alongside this one.

Next steps and related reading for Australians: apply for your Cambodia eVisa when you are ready to lodge, bookmark our Cambodia visa hub for Australian citizens as the single canonical reference, skim the FAQ on Cambodia visa business visa for quick answers, and use our glossary of Cambodia visa terms to decode any acronym in this guide.