Most people crammed in a swimming cap
Kerstin Droste and Team
4 people
Germany (Mainz, Rheinland Pfalz, Germany)

The most people crammed in a swimming cap is 4 and was achieved by Team Badekappe (Germany) on the set of ZDF Fernsehgarten, in Mainz, Germany, on 19 July 2015.

For this record a normal size swimming cap was used, it was stretched underwater by a team of six and then 4 participants entered the cap sitting into it and pulling the rim of the cap to their waists without breaking it.