Helen Butler, her partner Terry Fuggle and their friend Steve King had no idea of the show they were in for when they set sail from Portsmouth.
They headed for fishing grounds at Bracklesham Bay - and arrived to find themselves soon in the company of at least 20 dolphins.
'It was absolutely incredible' said Helen.
'We spotted them a way off soon after we arrived but they didn't seem interested in us.
'We were drifting fishing about a quarter-of-a-mile offshore, motoring back to the start point as the tide took us. The dolphins disappeared but later in the afternoon they were back - and much closer.
'They were swimming all around us - to the port side, starboard, forward and behind us - and they looked absolutely majestic. Steve and I both started filming them.
'Then as we motored back to the start point again, two of them took the lead in front of the bow. They were racing and they seemed to know exactly where the boat was behind them.
'They clearly absolutely adored being in the wash of the boat.'
Helen and Terry, who live in Cosham, had met up with Steve, from Aldershot, to take Terry's boat the Lorna Ellen from the Fountain Lake Angling Club moorings near Whale Island out to Bracklesham Bay.
'We have been there often and have seen dolphins but never like this' said Helen. 'The water was so clear - we could see them beneath the waves as well as when they leapt out. I feel really privileged.'
The unexpected show led to a lack of concentration on the task in hand though. 'It wasn't a great day's fishing - I think we caught a couple of plaice!' added Helen.