Your flight lands at Banjul International Airport, also called Yundum, the only international airport in the country. The smart move is to set up your MegaEsim before you fly. Install it at home on your own wifi, then leave it turned off. When the plane lands and you reach the gate, switch the line on. By the time you walk through the arrivals hall you already have signal.
The MegaEsim line connects to Africell, one of the main networks in The Gambia. Africell was the first operator in the country to offer eSIM, and its coverage around the airport and the coast is solid. You skip the kiosk queue, the passport photocopy, and the ten minute wait that a local SIM still needs.