The excellent Ajara Njoya scored the only goal of the game in the first half and Cameroon were largely in control but did finish the game with 10 players after a late red card.
They join Senegal in advancing to the 10-team global playoffs in New Zealand in February, where they will contest the three remaining spots available at the finals.
The African duo join Taiwan, Thailand, Haiti and Panama, who have also booked their places in that tournament.
Senegal did so as they defeated Tunisia on penalties in an earlier repechage game at the Women’s Africa Cup of Nations on Sunday.
Njoya forced an excellent stop from Botswana goalkeeper Maitumelo Boseja as she had a clear pre-game plan to test The Mares stopper from distance.
She had another go shortly afterwards that was simpler for Boseja before she made it third time lucky on the stroke of halftime.
Njoya unleashed another strike from 30-yards that took a slight deflection off a defender and nestled into the bottom corner of the net.
Botswana offered very little going forward in the first half, though they did have their fair share of the ball.
It was shaping up as a one-on-one battle between Njoya and Boseja as the former broke on the right-hand side of the box and forced another good save from the goalkeeper early in the second period.
Botswana had a rare shot at goal as Refilwe Tholakele forced a good save from Cameroon goalkeeper Ange Bawou, and from the resultant corner the latter rather flapped at the ball as it dropped onto the top of the crossbar.
Cameroon were reduced to 10 players after substitute Fadimatou Aretouyap received a straight red for a stamp with six minutes left in the contest.