In January 2026, French Guiana detected its first confirmed chikungunya case, initiating a second outbreak after the first one which occurred in 2014/15. The expected seroprevalence for 2026 is estimated at 16.2%, with the virus likely spreading eastward from the west of French Guiana. The causative East/Central/South African (ECSA) strain, lacking the vector-adaptive E1-A226V mutation, may reduce transmission risk in mainland France and Europe, but Caribbean Islands remain vulnerable due to the vector's presence.