I just got back from three weeks split between Vietnam, Thailand, and a few days in Malaysia. It was the longest trip I've taken in a while and I came back with some strong opinions about what gear and apps are actually worth bringing versus what sounds good in packing guides but doesn't hold up in practice.
This isn't a travel itinerary post — there are plenty of those. This is more about the practical logistics side, which is what I always want to read before a trip and can never quite find in the form I want.
I got a local SIM at the airport in Hanoi on arrival. The whole process took about 15 minutes and cost the equivalent of maybe $8 for 30 days of data. Coverage was fine everywhere I went except one very rural stretch of road north of Hoi An where it dropped out for about an hour.
I didn't bother with an eSIM this time. The price difference wasn't worth it for a trip this length and I like having a physical card I can swap back to when I get home. If you're doing a shorter trip and don't want to deal with finding a SIM vendor, eSIM makes more sense.
Google Maps offline maps, downloaded before leaving each city. In Vietnam especially, the addresses don't always match what's on the ground, so I found myself relying more on landmarks than on the turn-by-turn directions. After a couple of days I stopped fighting it and just used the map visually rather than following instructions.
Grab (the regional equivalent of Uber) was reliable in every city I visited. I only had one driver who seemed confused about where I was going and that resolved itself after a brief back-and-forth.
Cash is still king in Vietnam outside of the major cities and tourist areas. I withdrew from ATMs as needed rather than bringing a large amount from home. The fees were annoying but manageable. In Bangkok and Kuala Lumpur, card acceptance was much more widespread and I barely needed cash.
I brought a backup card from a different bank in case of ATM issues. Didn't need it, but I always do this and it's one of those things where the one time you don't bring it is the time you'll need it.
A packable rain jacket that I carried the entire trip and used once. A power bank that turned out to be heavier than useful given how many cafes and guesthouses have outlets. And a travel pillow that I used on exactly one bus ride and resented carrying the rest of the time.
The theme is: things that solve problems you imagine having versus problems you actually have. I'll probably make the same mistakes on the next trip.