This footage was taken by a jet ski-rider in Falmouth Bay on Saturday.
The rider, from Chough Productions, said: "It followed me for over ten minutes.
"Every time I stopped he would pop up beside me and wait for me to start again.
"I am driving a jet ski which has no moving external parts like a propeller so the dolphin was safe from harm.
"For the record, I do not chase dolphins, this one just wanted some one to play with."