The first bomb exploded at a restaurant in Narathiwat, one of the three violence-plagued provinces, at 0630 (1130 GMT).
A second bomb went off five minutes later just 15m from the restaurant.
The wounded included three police officers, police said, adding that at least one Thai man was in a critical condition. Police declined to give details of the Sunday blasts, which were under investigation.
More than 1000 people have been killed in Thailand's three southern provinces since January 2004.
Last week a former militant and his eight family members were gunned down in a revenge attack in Narathiwat.
Authorities variously blame the daily attacks in Narathiwat, Pattani and Yala provinces on Islamic separatist fighters, organised criminals or local corruption.