| unworn_swimsuit | swimsuit | |
| unworn_wig | wig | |
| upper_teeth_only | teeth | |
| upright_piano | instrument piano | |
| upright_straddle | straddling | |
| upscaled | resized | |
| upside-down_book | book | |
| upside-down_kiss | kiss | |
| urakata_(uracata) | banned_artist | |
| uraken | banned_artist | |
| uranami_(photographer)_(kancolle) | character:uranami_(kancolle) | |
| urban_camouflage | camouflage | |
| urethral_beads | sex_toy | |
| urim_(paintur) | banned_artist | |
| usagizado | banned_artist | |
| used_condom | condom | |
| used_condom_on_penis | condom condom_on_penis penis used_condom | |
| ushio_(hinamatsuri)_(kancolle) | character:ushio_(kancolle) | |
| ushio_(new_year)_(kancolle) | character:ushio_(kancolle) | |
| ushio_(swimsuit)_(kancolle) | character:ushio_(kancolle) | |
| ushio_(tsuyu)_(kancolle) | character:ushio_(kancolle) | |
| ushio_(valentine)_(kancolle) | character:ushio_(kancolle) | |
| usirome | banned_artist | |
| ussan_(uzi) | banned_artist | |
| uss_enterprise_ncc-1701 | uss_enterprise_(star_trek) | |
| uss_enterprise_ncc-1701-a | uss_enterprise_(star_trek) | |
| uss_enterprise_ncc-1701-b | uss_enterprise_(star_trek) | |
| uss_enterprise_ncc-1701-d | uss_enterprise_(star_trek) | |
| uss_enterprise_ncc-1701-e | uss_enterprise_(star_trek) | |
| usugumo_(race_queen)_(kancolle) | character:usugumo_(kancolle) | |