Switzerland → Réunion
Switzerland plugs
Type C
Type JRéunion plugs
Type C
Type EShared plug type: C
Compatibility: Compatible
Voltage — Switzerland 230V — Réunion 230V
Voltage is the same. Your devices should work normally.
Device compatibility (phones)
Phones almost always support 100–240V, so yours should work safely. Check your charger label to confirm.
You likely only need a plug adapter (if socket shapes differ). Voltage is close between these countries.