More than 2900 people took the 20-minute journey from Portobello to Kirkcaldy yesterday, an increase of 25 per cent on the first day. The craft made 26 journeys yesterday.
Eyewitnesses reported queues of more than 100 at Portobello.
Stagecoach spokesman Steve Stewart said: "We put on extra return trips to cope with the unprecedented demand.
"It's been a runaway success. It shows there is an appetite for an alternative form of public transport.
"It proved so popular that many people had to queue for quite sometime to get aboard. But in the end they all did. No one missed out."
Jenny Mollison, 58, a gardening consultant from Musselburgh, said: "It was just incredible. There were queues going right up the beach. People were having to wait for hours to get on it."