Mentions of several watercraft have been found in the code - jet skis and RHIB inflatable boats. Both entries refer to multiplayer, which confirms that work on naval gameplay is already underway. The files state:
Game/GlacierMP/Kits/Vehicle_Neutral_Boat_JetSki
Game/GlacierMP/Kits/Vehicle_Neutral_Boat_RHIB
The name Glacier is used as the code name for Battlefield 6, and MP stands for multiplayer mode.
Previously, the developers noted that players' requests for the return of naval battles "did not go unnoticed." When exactly they will appear is unknown. Judging by the content of the first season, where there are almost no water maps, it will probably be a long wait. But the series has already released separate seasons dedicated to naval operations, and Battlefield 6 may repeat this step.