Official said one bomb affected the city's airport, while another damaged part of the police station, Colombia Reports said.
Whether there were injuries or deaths wasn't reported.
The third blast apparently was directed against an anti-narcotics unit of the Colombian army, officials said.
Authorities were working to determine who was responsible for the attacks.
Colombia Reports said Tumaco is considered a strategic city for drug traffickers because of its location near some of the country's main coca-growing areas and Pacific Ocean.