Dorset Police have identified the deceased as 12-year-old Sunnah Khan and 17-year-old Joe Abbess after they died in the water off Bournemouth beach on Wednesday.
Another eight people were injured in the incident. Joe was from Southampton while Sunnah was from Buckinghamshire, the force said.
Joe’s family issued a tribute to him through Dorset Police, saying: “We are heartbroken and devastated at the death of our Joe. He was a wonderful son and brother who is sadly missed.
“His family and friends will always love him, and we are incredibly proud of the fabulous young man he was. He was kind and generous, loving and caring, hardworking and funny.
“Joe was a talented trainee chef, with a bright future ahead of him. We were privileged to have him in our lives for 17 years, and we are so sorry he will never fulfil his dreams and ambitions.
“He was enjoying a day at the beach on Wednesday, and we would like to thank his friends and all of the emergency services who helped him, when this tragedy unfolded.”
A man in his 40s who was “on the water” at the time of the incident was detained on suspicion of manslaughter and released on Thursday while police investigations are ongoing.
At around 4.30 p.m. on Wednesday, paramedics called Dorset Police to report that there were individuals on the beach close to Bournemouth Pier who needed help.
Ten persons were pulled from the water as emergency personnel arrived on the scene. The police claimed to have saved Joe and Sunnah from the water, but they eventually passed away in hospitals.