Samsung Galaxy S21 5G Bands

2G B2 (1900), B3 (1800), B5 (850), B8 (900)
3G B1 (2100), B2 (1900), B4 (1700/2100), B5 (850), B8 (900)
4G B1 (2100), B2 (1900), B3 (1800), B4 (1700/2100), B5 (850), B7 (2600), B8 (900), B12 (700), B13 (700), B14 (700), B18 (800), B19 (800), B20 (800), B25 (1900), B26 (850), B28 (700), B29 (700), B30 (2300), B38 (2600), B39 (1900), B40 (2300), B41 (2500), B46 (5200), B48 (3800), B66 (1700/2100), B71 (600)
5G N1 (2100), N2 (1900), N3 (1800), N5 (850), N7 (2600), N8 (900), N28 (700), N40 (2300), N41 (2500), N66 (1700), N71 (600), N77 (3700), N78 (3500), N79 (4700), N260 (39GHz), N261 (28GHz)

Coverage in Mongolia

2G B3 (1800)B8 (900)
3G B1 (2100)
4G No
5G No

Operators of Mongolia

2G 3G 4G 5G
Mobicom B3 (1800)B8 (900) B1 (2100) No No
G-Mobile No B1 (2100) No No
Skytel No B1 (2100) No No
Unitel B8 (900) B1 (2100) No No