New Hampshire Marine Patrol said they heard about a 70-foot boat on fire near Little Harbor in New Castle on the Piscataqua River.
The 2007 Marlow named "Elusive" was heading towards Wentworth Marina when it started filling up with smoke, according to passengers.
The Coast Guard said the people on the boat were evacuated safely by a Good Samaritan.
Marine Patrol said three people and two family dogs jumped into the water and were recovered.
Jarrod Tubbs, 33, of Jupiter, Florida, Arthur Watson, 67, and Diane Watson, 57, both of New Canaan, Connecticut were treated and released from Portsmouth Hospital, Marine Patrol said.
They were initially treated for minor injuries at Wentworth Marina by New Castle Fire Dept. and Newington Ambulance, according to the Portsmouth Fire Dept.