The Samsung Galaxy S21 announcement and release are both expected in January 2021. The S21 is expected to come in 3 models: S21, S21 Plus, and the S21 Ultra. The current rumors are expecting a January 14th announcement, which would coincide with what Samsung.com sent existing customers yesterday about their virtual waiting room:
However, the Samsung Galaxy S21 phones may be announced earlier that week. CES 2021 will kick off on January 11th and wrap up on January 14th. While Samsung is currently not slated for a keynote, there is a Verizon keynote on January 11th that may make mention to devices supporting the 5G network including the new S21 lineup.
You can join the virtual waiting room now and reserve the next galaxy smartphone by visiting samsung.com/us/smartphones/the-next-galaxy/reserve/