By The Escape desk · Last verified 4 October 2026
For most short trips from Singapore, a telco roaming data pack and a travel eSIM now cost about the same, and both are far cheaper than pay-per-use roaming. As of October 2026, Singtel’s ReadyRoam Asia pack gives 6GB for S$18, valid 30 days in 19 destinations including Japan and South Korea, and its Neighbours pack for Malaysia, Indonesia and Thailand starts at 1GB for S$5. A travel eSIM such as Airalo’s Japan plan costs US$26.50 for seven days of unlimited data. The real difference: roaming keeps your Singapore number for calls and SMS one-time passwords, while most travel eSIMs are data-only.
The best choice depends on how much data you use and how much you rely on your Singapore number. Here is how to decide in a minute.
Quick facts
- Singtel ReadyRoam Neighbours: 1GB for S$5 or 6GB for S$12, valid 30 days.
- Singtel ReadyRoam Asia: 6GB for S$18, valid 30 days, 19 destinations.
- Singtel ReadyRoam Worldwide: 6GB for S$40, valid 30 days, 135 destinations.
- Buying a second Singtel pack within 30 days unlocks unlimited data after 12GB.
- Airalo Japan eSIM: unlimited data from US$11.50 for three days to US$69 for 30 days.
- Your phone must support eSIM and be carrier-unlocked to use a travel eSIM.
Roaming pack or eSIM: side by side
| Telco roaming pack | Travel eSIM | |
|---|---|---|
| Example price (October 2026) | Singtel ReadyRoam Asia: 6GB, S$18, 30 days | Airalo Japan: unlimited, US$26.50, 7 days |
| Singapore number for calls and SMS | Works as normal; call and SMS charges may apply | Stays on only if you keep your main SIM active alongside |
| Set-up | Buy in your telco’s app; nothing to install | Install the eSIM profile before you fly, switch on arrival |
| Best for | Short trips, light to moderate use, people who need OTPs | Heavy data use, longer trips, single-country stays |
| Risk | Pay-per-use charges if you exceed or forget the pack | Wrong data line selected, or phone not compatible |
A worked example: a week in Tokyo
You will spend seven days in Japan, using maps, messaging and some video, around 5GB in total.
- Singtel ReadyRoam Asia: one 6GB pack at S$18 covers it, with 1GB to spare, and your number keeps working for bank SMS codes.
- Airalo seven-day unlimited: US$26.50, which costs more than S$18 once converted to Singapore dollars, but you never need to watch your usage.
- Heavy user, about 10GB: two Singtel packs (S$36) versus the same US$26.50 eSIM. The gap closes, and the eSIM’s unlimited data starts to look like the better deal; check the day’s exchange rate.
Prices for other telcos and eSIM sellers differ, so run the same sum with your own provider’s current rates.
Setting up a travel eSIM safely
- Check that your phone supports eSIM and is not locked to one carrier.
- Buy the plan and install the eSIM at home over Wi-Fi; keep the QR code or install link private.
- Label the lines clearly, for example “SG” and “Travel”.
- On arrival, set mobile data to the travel eSIM and turn on data roaming for that line only.
- Turn off data roaming on your Singapore SIM, but leave the line on if you need calls and SMS one-time passwords.
- Delete the eSIM after your trip, once its data is used up.
The WahLiao Verdict
For a short trip in Asia with normal use, buy your telco’s roaming pack before you fly: it is cheap, takes seconds, and keeps your bank’s SMS codes arriving. Choose a travel eSIM for long trips, heavy streaming or if your telco’s packs are pricey, and keep your Singapore line on with its data roaming off. Whatever you pick, never leave the airport on pay-per-use roaming.
Questions people ask
Will I still get bank OTPs with a travel eSIM?
Yes, if you keep your Singapore SIM switched on alongside it in dual-SIM mode. Check your telco’s charges for receiving SMS overseas.
Do travel eSIMs come with a phone number?
Most, including the Japan plans quoted here, are data-only. You can still call and message over apps such as WhatsApp.
How do I avoid a roaming bill shock?
Buy a data pack before you fly, or switch off data roaming on your Singapore line. Check your telco’s app for the pack balance during the trip.
Is buying a local SIM at the airport still worth it?
It can be for long stays, but you swap out your Singapore SIM and may queue on arrival. eSIMs and roaming packs have made it less necessary.
Sources: Singtel, ReadyRoam roaming plans and prices; Airalo, Japan eSIM packages. Prices as published on 4 October 2026 and subject to change. The Escape explains; it does not advise.
Read next: Mobile Plans in Singapore: SIM-Only, Contracts and the Cheaper Networks · Visiting Japan: The 90-Day Visa-Free Stay · Back to The Escape
For what’s worth it this week, with the bill shown, read The WahLiao Week.
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