Your EU SIM will incur standard international roaming charges here. Consider a local SIM or eSIM.
Roaming Zone Memberships
The six CEMAC member states — Cameroon, Central African Republic, Chad, Republic of the Congo, Equatorial Guinea and Gabon — validated a draft Community Regulation for a One Network Zone in 2020. The regulation aims to eliminate roaming surcharges for voice and data within the zone. Implementation is ongoing with gradual price reductions.