Another 48 people were wounded, the Chadian government said in a statement, after provisional figures by security sources late Saturday put the death toll at 37 with 52 wounded, some seriously.
"The terrorist group Boko Haram has hit Baga Sola," the statement added without giving details on the attacks. But it said the situation was under control and urged the population to show greater vigilance.
The powerful explosions struck at around 4:00 pm (1500 GMT) yesterday, with one blast targeting the fish market at Baga Sola and the other two occurring at a refugee camp on the outskirts of the city.
Humanitarian and security sources say several people blew themselves up in the middle of a crowd.
Lake Chad is shared between Nigeria, Niger, Cameroon and Chad.
The Chadian army has since the start of this year been involved in a regional offensive against Boko Haram, which has pledged allegiance to the Islamic State group operating in Syria and Iraq.