UPDATE: an official trailer has been shared by THQ Nordic and the game is slated for release on June 23rd, 2020.
Steam has updated the dates on the game's page and Amazon.co.uk has sent out an e-mail with new expected delivery dates, both aiming around the 23rd of June. Looks like an official announcement for the release date will show up very soon.
At this very moment, there are no official mentions yet about any release date for the game. The Steam page, for instance, has no date written down, but rather (When) I'm ready! Hopefully, an announcement will come along soon with an official date.
SpongeBob SquarePants: Battle for Bikini Bottom - Rehydrated is a remake of the 2003 original. The remake will contain more content, however, as it will have a new multiplayer mode as well as cut content from the original (including a boss fight with Robo-Squidward).
The title is due to release on Pc, PlayStation 4, Xbox One and Nintendo Switch.