If I am visiting both Brazzaville and Kinshasa, will this CoreESIM plan provide coverage in both locations?

No, this CoreESIM plan is geo-restricted to the Republic of the Congo. Upon crossing the Congo River into Kinshasa, which is the capital of the Democratic Republic of the Congo (DRC), this eSIM will cease to function. These are two separate countries, each with independent telecommunications networks. For travelers visiting both nations, CoreESIM recommends selecting a regional eSIM product or two separate country-specific eSIMs that explicitly list both the Republic of the Congo and the DRC to ensure continuous service.