After an aggressive start with tackles flying in from both sides, Honduras almost took a shock lead in the eighth minute when Ramon Nunez fed Emil Martinez 25 yards from goal. He squared the ball to Rigoberto Padilla who dragged his effort just wide of the upright.
A slip of concentration almost cost the central Americans dear when Arsenal's Alexandre Song pounced on a loose ball, but his shot sailed just over the bar. Shortly before the half-hour mark Frank Songoo and Christian Bekamenga combined well, with the latter forcing Honduras goalkeeper Kevin Hernandez into a smart low save.
The reply was almost instant. Nunez fizzed a free-kick wide of the target as the Qinhuangdao crowd erupted into several laps of Mexican waves, but there was still time for one more chance for the Africans when Gustave Bebbe headed Aurelien Chedjou's corner straight at the keeper on the stroke of half-time.
It was all Cameroon in the second half as they tried to convert their time on the ball into clear-cut chances and goals. Bekamenga had four chances to put his side ahead, but was frustrated by the assistant referee's flag, his own finishing and some last ditch defending.
Supplied on three of those occasions by the lively Chedjou, he had a header from a corner ruled out for holding his marker in the 49th minute, fired over in a one-on-one situation with Hernandez five minutes later and, perhaps the most frustrating of all, had a goalbound effort directed on to the post with 18 minutes to go.
In contrast, Honduras were limited to a speculative shot from distance from Padilla as they tried to negate the Indomitable Lions' goal threat.
Cameroon coach Martin Ndtoungou made two substitutions to try and find a goal, but in the end it was created - and finished by two members of his starting 11.
Songoo found Mbia on the edge of the area and he struck a sweet right-footed shot into the corner of the goal to spark their dancing celebration.
In the latter stages, Alain Olle hit the woodwork with the luckless Bekamenga missing the rebound, but in the end, it proved inconsequential as Cameroon recorded their first victory of the tournament. They now meet Italy in their final group game, still needing a result to make sure of a place in the last eight.