Every Australian carrier now sells an international day pass. Turn it on, land, and your phone works like it does at home for a flat daily fee. It's genuinely convenient, and for a two-day trip it's hard to argue with.
The problem is that the daily fee keeps ticking. Here's how the maths works out on real trips, and what you give up either way.
What the carriers charge
Rates change, so check your carrier before you fly, but at the time of writing:
Telstra International Day Pass: around A$10 a day in most popular destinations, with a daily data allowance and unlimited calls and texts.
Optus Roaming: around A$5 a day for a smaller daily data allowance, with a higher tier available.
Vodafone $5 Roaming: A$5 a day to use your Australian plan's inclusions overseas, in eligible countries.
The catch in all three is the daily data cap. Blow through it and you're either throttled or buying another pass. And "a day" is a 24-hour block from first use, so a late-night arrival can cost you a day you barely used.
Trip one: 10 days in Bali
Day pass: 10 days at A$5 to A$10 is A$50 to A$100. Each day has its own data cap, and nothing rolls over.
eSIM: a 10GB Indonesia plan valid for 30 days is A$19.45. Use it however you like across the trip.
The eSIM is A$30 to A$80 cheaper, and 10GB spread across ten days is more usable than ten small daily buckets.
Trip two: three weeks in Europe
Day pass: 21 days at A$10 is A$210. At A$5 it's A$105, if your carrier covers every country on your route at that rate.
eSIM: a single Europe plan covering 30-plus countries, or individual country plans if you're only visiting one or two. Either way you're looking at a fraction of the day-pass total for a normal amount of data.
Over three weeks, the day pass costs more than a return flight to Bali.
What you give up with an eSIM
Be honest about the trade-offs. An eSIM is data only. That means:
No regular calls on the eSIM. WhatsApp, FaceTime, Messenger and Zoom all work perfectly over data, and that's how most people call home anyway. But if you need to phone a local restaurant, you're on your Australian SIM at roaming rates.
Your Australian SIM still needs to be in the phone to receive SMS codes from your bank. That's fine, it just needs data roaming turned off.
Setup takes five minutes instead of zero. You install the eSIM before you fly and switch your data line on arrival.
What you give up with a day pass
Money, obviously, on anything longer than a weekend.
Data. Daily caps are small and don't roll over.
Network choice. Your carrier's roaming partner might not be the best network in the country. An eSIM provider picks networks with good coverage for travellers.
Speed, sometimes. Roaming traffic can route back through Australia, which adds latency. Local eSIMs connect locally.
The setup that gives you the best of both
This is what most Roamly customers do, and it's why dual SIM phones make travel so much easier now:
Keep your Australian SIM in the phone. Turn data roaming off for that line.
Install the travel eSIM before you fly and set it as your mobile data line when you land.
Make calls home on WhatsApp or FaceTime over the eSIM's data.
If you absolutely must make a regular call, do it on your Australian line and accept the one-off roaming charge, or activate a single day of the day pass for that day only.
You keep your number, your bank codes keep arriving, and you're not paying A$10 a day for the privilege.
When roaming is actually the right call
Roaming wins for a 24 to 48 hour trip, especially a work trip where you need to take calls on your normal number. It also wins if your phone doesn't support eSIM or is carrier-locked. And if your Australian plan already includes some international roaming days, use them.
For a holiday of a week or more, it's not close. Find a plan for your destination, or check whether your phone supports eSIM first.