Usually the local network rather than the eSIM — congestion, weak signal or an Unlimited Plan past its daily full-speed allowance
A travel eSIM does not throttle anything of its own accord. It puts you on local networks, and the speed those deliver varies by street and by hour exactly as it does for people who live there.
The Usual Causes
- Congestion. Evenings, city centres, festivals, airports at arrival time
- Weak signal. Rural areas, basements, underground trains, thick-walled buildings
- Your handset. An older phone supports fewer frequency bands and cannot reach the faster ones
- Fair Usage on an Unlimited Plan. Past the daily full-speed allowance, speed reduces until the next reset
- The network chosen. Where a plan allows several, the phone does not always pick the best one
Fixes, in Order of How Often They Work
- Turn flight mode on for ten seconds and off — the phone re-scans and often lands on a better network
- Restart the phone
- Move — one street, or out of a basement, changes more than any setting
- Select a network by hand in mobile network settings, then set it back to automatic later
- Turn off 5G if coverage is patchy; constant switching between network types is slower than steady 4G
On an Unlimited Plan, reduced speed still carries messaging, maps, email and web pages. Full speed returns automatically at the next daily reset — nothing needs buying.
Compare with someone next to you on a local network. If theirs is slow too, it is the cell rather than your plan, and moving is the only fix either of you has
