Southeast Asia eSIM

Seven countries on one line: Thailand, Singapore, Vietnam, the Philippines, Indonesia, Malaysia and Cambodia. That maps neatly onto the classic overland loop, Bangkok down to the islands, across to Siem Reap, on to Ho Chi Minh City, and equally onto a Singapore work week with a weekend in Kuala Lumpur. Buy it when your route touches at least three of the seven.

The size ladder runs from 1 GB over 7 days at $3.99 up to 20 GB over 30 days at $40.99. The one worth noticing is 50 GB over 180 days at $90.99, which is built for a long stay rather than a holiday: six months of validity, enough headroom to work from a laptop, and no monthly re-purchase.

Border hops are the point of this plan. Fly Bangkok to Denpasar or cross overland into Cambodia and the eSIM re-registers on a network in the new country, still drawing on the balance you already paid for. Nothing to buy again, nothing to reinstall. If the phone still shows the previous country's network after a crossing, toggle Airplane Mode once to force a fresh registration.

The limitation is the edge of the list. Laos and Myanmar sit outside these seven, so a Luang Prabang or Yangon leg leaves you without data. Laos is covered by the wider 20 country Asia plan, Myanmar by neither. A daily option also exists here: 1 GB at full speed per day, then reduced speed, from $26.99 for 7 days. The line is data-only, no number, no SMS.

• Install before your outbound flight; the clock starts at first connection in the region, not at purchase.
• On island and boat days in Indonesia or the Philippines, download offline maps first; you will lose signal over open water.
• Grab, Gojek and hotel bookings all need data at the airport, so set the eSIM as your data line before landing.
• Keep your usual SIM in the phone for bank codes; this eSIM has no number and cannot receive SMS.
• Hotspot works, which is handy for a hostel laptop session, but tethering will drain a 3 GB plan quickly.