A teenage boy has drowned at Glenelg beach in Adelaide, the second drowning death at the same beach in just over a week.

Surf Life Saving SA said the 15-year-old from Goodwood was pulled from the water after he got into trouble under the jetty late this afternoon.

Paramedics responded and gave him CPR, but he died at the scene.

Surf Lifesaving SA commended a group of boys for their bravery after they tried to save the teenager.

A spokesperson said the boys jumped from the jetty to reach him and dragged him to shore before starting first aid treatment.

It is unclear how long the boy had been in the water, but it is understood his mother, who was at the beach, hadn't seen him for at least a couple of hours.

On December 10 a 15-year-old Indian girl drowned at a different area of the same beach, after being swept into the sea from the breakwater.

Four other girls, also from India, were rescued but the 15-year-old's body was found the following day.

The group were in Adelaide for the Pacific School Games.

The Indian girl's death prompted the local council to erect new signage warning the public the breakwater would now be off limits.