The stretch of coastline had been off limits to the Palestinians living in the nearby fenced-off refugee camps and towns of Khan Yunus and Rafah.
Mahmud Barbakh and Muhammad Jaroun, Palestinian teenagers who grew up just a few minutes from the Mediterranean but had never been to the beach before, were overwhelmed by the experience.
On Monday, they waded into the waves with their jeans rolled up, then abandoned all caution and threw themselves into the surf.
"It was the sweetest thing in the whole world," said 15-year-old Mahmud, beaming.
The boys' beach adventure was made possible by Israel's withdrawal from the Gaza Strip.
In southern Gaza, Israeli settlements took up the beachfront for three decades, and Palestinians in that area were barred by Israeli troops from reaching the Mediterranean.
A few hours after the last Israeli occupation forces left on Monday, hundreds of Palestinians, including many giddy teenagers, enjoyed the water.
One used a refrigerator door as a makeshift surfboard. Nearby, youngsters collected spent Israeli bullet casings, stuffing them into empty bottles.
Palestinians, kept from the sea for
decades, could not wait to dive in
Adults also had fun. Muhammad Deir, 41, said he closed his building supplies store in celebration.
"The only job I have today is to go to the beach and the border," he said, as an Israeli navy boat patrolled off the coast.
However, the celebrations were marred by the drowning of five Palestinians in the Mediterranean, hospital sources said.
Further north, Palestinian motorists were still waiting hours at the main Israeli checkpoint on Gaza's north-south road, which was a common occurrence under Israeli rule.
The Abu Holi checkpoint was still gridlocked on Monday, with hundreds of cars backed up in each direction.
The dozen or so Palestinian policemen posted at the checkpoint were unable to untangle traffic after thousands of Palestinians got in their cars, heading to beach picnics and tours of former border areas.
Aisha al-Farra, from the town of Khan Yunus, said she had already been waiting at Abu Holi for three hours, her second attempt of the day to cross the checkpoint.
She said she was determined to get through, in the hope of reaching a small fruit orchard she said belonged to her family but had been off-limits during Israel's rule.