Two motorbike riders from France and a young man from Hastings were taken to hospital with serious injuries after a crash on the Marsh Road at Hooe.
The accident happened at 10.30am on the A259 between a blue Honda Jazz which collided with a Harley Davidson bike.
The Honda then spun around and collided with a white Citroen Relay which then hit another motorbike.
A 40-year-old man from France, who was riding the Harley Davidson, was taken to the Royal Sussex County Hosptial with serious injuries.
The rider of the other motorbike, a 48-year-old woman also from France, was also taken to the Royal Sussex County Hospital in Brighton with serious injuries.
A 26-year-old man who was a passenger in the Citroen was from Hastings.
He was taken to the Eastbourne District General Hospital with slight injuries.
No-one else was injured. It is believed the victims suffered broken legs in the accident. Witnesses are asked to contact police on email@example.com quoting Op Exbourne.