At least 10 people including six Italian tourists and four Kenyans are missing after a boat they were in capsized off the Garoda beach in Watamu, Kilifi.
Police and Kenya Wildlife Service officials said rescue operations were ongoing after the Saturday morning incident.
The boat was on a marine excursion, carrying about 40 tourists, both Italian and Kenyans when it capsized.
They were among others following the dolphins, one of the objectives of the marine safari in the area when the incident happened.
Others aware of the operations said an unknown number of Kenyans drowned while the Italians managed to reach the shore on other boats.
“Six Italian tourists have not yet returned but should be on board another tourist boat,” the officials said.
“The six Italian tourists would be on another boat that set to see the dolphins.”
Other nearby boats quickly went to the scene of the accident and took the unfortunate on board, but some Kenyans were unable to board.
The area has the best-known beaches in Kenya and is frequented by both local and international tourists.