What happens if you fly without setting anything up

The published rates

Checked 1 September 2026, from each carrier’s own material. These apply when no pack, pass or add-on is active.

Optus is deliberately absent from that table, and the reason is interesting. Their Daily Roaming product auto-activates the moment you use your service in an eligible destination, so in practice most Optus customers never reach pay-as-you-go rates. They reach a $5 charge instead, and then another one each time 5GB is used.

Everyday Mobile is absent too, because its public page directs customers to an add-on for data, calls and sent texts while leaving incoming SMS free. It does not publish a pay-as-you-go rate, so we are not going to invent one.

Belong is absent because it sells a pack rather than pay-as-you-go use. Its A$30 pack gives you 3GB, 150 minutes and unlimited standard SMS for 15 days once active. Without a pack, eligible plans can still receive SMS and use wi-fi calling for free.

Coles works differently again. International roaming is available without a setup switch, but the public product is purchased roaming credit rather than an automatic daily pass. The credit expires 30 days after purchase. Its rates page is destination-specific, so the row above reports only the nine popular destinations we checked: New Zealand, the United States, China, the United Kingdom, Singapore, Indonesia, Hong Kong, the Philippines and South Korea. All nine showed the same rates, but Coles warns that rates can differ by country and change frequently.

ALDI’s premium destinations include Brazil, East Timor, Egypt, Israel, Malta, Mexico, Nigeria, Qatar, South Africa and the United Arab Emirates.

Which carriers fail safely, and which do not

This matters more than the rates, because the rates only apply if something is switched on.

ALDI Mobile fails safely. Roaming is off by default and you have to enable it in My ALDI Mobile. Their own advice is to do it “whilst in Australia, before you leave.” If you forget, your phone simply does not work overseas. That is annoying at the airport and it costs you nothing.

Telstra requires activation too. The Day Pass must be switched on in My Telstra before you travel, and they note it “can take up to 2 hours to activate”. Leave time, and do it before you fly rather than in the queue at passport control.

Optus fails expensively, by design. Their pages state Daily Roaming is “auto-activated, so if you don’t turn it off it’ll automatically trigger when you start using your Mobile service in an eligible Zone 1 destination.”

The trigger list is broader than people expect. Receiving a call charges you, even if you decline it. Receiving a text does not. And a voicemail diversion set to busy, no reply or unreachable “may trigger the service”, which means somebody else ringing your phone can start the charge without you touching it. The full detail is in how Optus daily roaming switches itself on.

Vodafone is mostly already on. Their pages state $5 Roaming “should be activated already for you”, with some older plans needing manual activation.

Coles says international roaming is available on all services without setup, but chargeable use draws from roaming credit you buy. That makes it different from both an auto-charged daily pass and an ordinary plan balance.

So the mental model is: if your carrier makes you switch roaming on, forgetting means no service. If your carrier switches it on for you, forgetting means charges. Neither is wrong, but they need different preparation.

Check which one yours is before you fly. The pack terms and enablement rules for every Australian MVNO are set out in Australian MVNO roaming packs compared, and the timing rules across all the carriers here sit in when your roaming day actually starts.

The ten second thing to do before you fly

Turn data roaming off on your Australian line.

On iPhone that is Settings, Mobile Service, select your Australian line, then Mobile Data Options, and switch Data Roaming off. On Android it sits under Network and internet, SIMs, your Australian SIM, then Roaming.

This does not stop calls or texts arriving. It stops the data side, which is where the per-megabyte charges come from.

Do it even if you have bought a pack, because a pack only covers the destinations listed for it. Step outside that list and you are back on the rates in the table above.

And do it even if you are using a travel eSIM, because otherwise your Australian line can quietly pull data in the background while the eSIM sits there doing nothing. Full walkthrough in the data roaming toggle.

What to buy before you go

Whoever you buy from, buy something. The failure here is not picking the wrong product, it is arriving with nothing arranged.

If you want calls and texts on your Australian number, a carrier pack is the answer and we do not sell an equivalent. ALDI’s Global Travel pack and Everyday Mobile’s Global pack both include voice and SMS. Optus Daily Roaming includes unlimited standard talk and text on phone plans.

If you mainly need data, a travel eSIM is usually the simpler shape, especially past a week. Our plans run 30 days rather than seven, start on first connection at the destination rather than at purchase, and are priced per destination.

Checked 1 September 2026, in Australian dollars. The SIM Shop is not registered for GST, so GST is not charged and the checkout total is what we charge you.

The setup we would actually recommend is both: Australian SIM in the phone with data roaming off so calls and texts still arrive, and a travel eSIM carrying the data. Our guide to keeping your Australian number working overseas covers the exact setup and the voicemail trap.

Questions people actually ask

What happens if I forget to turn off roaming?

It depends on your carrier. On ALDI Mobile and Telstra, roaming has to be switched on first, so forgetting usually means nothing works. On Optus, Daily Roaming auto-activates and a $5 charge can trigger from your phone simply being used, or from someone ringing you. On Vodafone, $5 Roaming is generally already active.

How much is Telstra roaming per MB?

$3.00 per megabyte without a Day Pass, per their published rates, along with $1.50 to $5.00 a minute for calls depending on destination.

Can I be charged without using my phone?

On Optus, yes. Receiving a call triggers the charge even if you decline it, and a voicemail diversion may trigger it. Receiving a text does not.

Is turning on aeroplane mode enough?

It stops everything, including the calls and texts you may want. Turning data roaming off on your Australian line is the more useful setting, because your number keeps working for voice and SMS.

Do I still get bank verification codes with data roaming off?

Yes. Those arrive as SMS, which is not data. On Vodafone and Everyday Mobile, receiving SMS overseas is free.

Which Australian carrier has the cheapest pay-as-you-go data?

Of the rates we could verify, ALDI Mobile at $0.50 per MB in most countries and Coles Mobile at $0.50 per MB across the nine popular destinations we checked. Both are rates to avoid rather than rates to use.

Does a travel eSIM stop roaming charges?

Only if you also turn data roaming off on your Australian line. The eSIM carries the data, but the Australian line can still pull data in the background unless you switch it off.

Sources

Telstra pay-as-you-go rates and Day Pass activation requirement, including the two hour activation note, from Telstra’s international roaming page, checked 1 September 2026. Vodafone pay-as-you-go rates and the note that $5 Roaming should already be active from Vodafone’s roaming rates page and international roaming page, checked 1 September 2026. ALDI Mobile pay-as-you-go rates, premium destination list and the requirement to enable roaming before leaving from ALDI Mobile’s international roaming rates and providers document, dated 17 June 2026, and their international roaming policy page. Optus auto-activation and trigger conditions from Optus’s own Daily Roaming support material, with full quotes in how Optus daily roaming switches itself on. Everyday Mobile’s add-on model and free incoming SMS from its international roaming page. Belong’s pack inclusions, activation and free basic overseas service from its travel pack page and international roaming help. Coles Mobile’s destination-level rates from its roaming rates page, and roaming availability and 30 day credit expiry from its international roaming FAQ, all checked 1 September 2026. The SIM Shop prices from our own product catalogue, checked 1 September 2026. GST position per the Australian Business Register, checked 1 September 2026. Rates change without notice.

Written by Lachlan, who runs The SIM Shop from Brisbane and answers the support email himself.