It was around midday on Saturday when lifeguard Janusz Burda noticed the youngster who appeared unconscious on his body board and immediately swam out to rescue him.
A spokesman for the RNLI said: “The young body boarder was spending the day at the beach with family, and was around 20 metres out to sea between the red and yellow flags when his seizures began.
“The boy’s brother was also nearby and his concern for his sibling made it clear that something was wrong.
“As Janusz was bringing the boy back to the beach, the father also swam out to assist.
“Once back on the beach, the casualty regained consciousness and after consulting with paramedics they continued to monitor him in case of further seizures.”
Following some observation and care from the Skegness lifeguards, the boy was reported to be fine.
Polish-born Janusz, 20, said: “As an RNLI lifeguard we receive comprehensive casualty care training and are equipped to deal with everything from a minor first aid through to a lifesaving rescue.
“The training immediately kicked in on Friday and I’m so pleased that we were able to assist and that the boy was okay and well to enjoy the rest of his day.”
RNLI Lifeguard supervisor, Arun Gray, added: “This is yet another reminder of why you should always swim between the red and yellow flags, and on a lifeguarded beach.
“Fortunately, Janusz was there on patrol and was able get to the casualty immediately, before the situation escalated and could have led to a completely different outcome, as the young boy’s brother and father may have got into difficulty themselves.”