Saint Martin → Eswatini
Saint Martin plugs
Type C
Type EEswatini plugs
Type C
Type M
Type NShared plug type: C
Compatibility: Compatible
Voltage — Saint Martin 230V — Eswatini 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.