It happened around 2:45pm in a section of the beach about three miles north from the town of Surfside.
A church group was out in the water and a 15-year-old boy from Needville was about waist-deep when he encountered a four-foot shark.
Freeport police say the teen was bitten twice, once on his left leg and once on his left hand.
"I hope this teenager grows up to be a cop and gets my back," EMT Zuandra Monnat said. "He fought off this shark. It bit his leg and he literally tore this shark off of him and that's how he got the lacerations to his hands."
Monnat happened to be on the beach at the time of the attack and provided first aid.
"Initially, I saw a boy who was brought onto the beach," she said. "As far as his injury goes, he was bitten on the leg. He had multiple lacerations on his hand. We bandaged that up using a multi-trauma, which is basically a very big, large bandaid and we got him over to Life Flight as quick as we could."
The teen was then transported to Memorial Hermann Hospital with injuries that are not life-threatening condition. Authorities say he was airlifted because of the nature of the injuries.
"Any time that you have that you actually use on a day-to-day basis, being your hands or your head or anything like that, it's more of a quality-of-life situation," Monnat said. "We want him to be able to have all the mobility of his hands and not lose with his hands. Everything was connected, it was just more of wanting to make sure everything continued to work properly."
Authorities say this was the first shark attack to be reported at Surfside beach in more than a couple decades.
"They've had shark attacks on the county beach and in Freeport, but here in Surfside, this is the first one in 25, 30 years," Surfside Assistant Police Chief Gregg Bisso said.
The teen's identity hasn't been released.