Firsty

Firsty runs a pay-per-day model rather than fixed plans, covering 185-plus countries globally. For Vietnam, you purchase daily passes with 8GB of full-speed data included per day, letting you activate connectivity only when you need it. This approach suits shorter trips or unpredictable travel schedules where committing to a multi-week plan doesn't make sense.

This suits short trips, layovers, or variable travel where you don't know exactly how many days you'll need connectivity. You avoid paying for unused days and can start or stop on a whim without committing to a monthly plan.