• SM U-1

• SM U-2

• Type U 3

• Type U 5

• Type U 9

• Type U 13

• SM U-16

• Type U 17

• Type U 19
  • SM U-21 (later Austrian SM U-36)

• Type U 23

• Type U 27

• Type U 31
  • some with Austrian flag

• SM U-42 (later Balilla)

• Type U 43
  • SM U-46 (later Japanese O-2)
  • SM U-47 (later Austrian SM U-36)

• Type U 51
  • SM U-55 (later Japanese O-3)

• Type U 57

• Type U 63
  • all under Austrian flag

• Type U 66
  • ex-Austrian U-7 through U-11

• Type UE I
  • some under Austrian flag
  • SM U-79 (later French Victor Réveille)

• Type U 81

• Type U 87

• Type U 93

• Type U 57
  • SM U-99 through
  • SM U-104

• Type U 93
  • SM U-105 (later French Jean Autric) through
  • SM U-114
  • SM U-108 (later French Léon Mignot)

{{German Type U 115 submarines|state=expanded}}

• Type U 115
  • SM U-115 through
  • SM U-116 incomplete

• Type UE II
  • SM U-119 (later French René Audry)
  • SM U-125 (later Japanese O-1)

{{German Type U 127 submarines|state=expanded}}

• Type U 127 / German Type Mittel U submarine?
  • SM U-127 through
  • SM U-134 incomplete
  • SM U-135
  • SM U-136
  • SM U-137 incomplete
  • SM U-138 incomplete

• Type U 139
  • SM Kapitänleutnant Schwieger (U-139) (later French Halbronn)
  • SM Kapitänleutnant Weddigen (U-140)
  • SM U-141

{{German Type U 142 submarine|state=expanded}}

• Type U 142
  • SM U-142
  • SM U-143
  • SM U-144
  • SM Kapitänleutnant Wegener (U-145)
  • SM Oberleutnant zur See Saltzwedel (U-146)
  • SM Kapitänleutnant Hansen (U-147)
  • SM Oberleutnant zur See Pustkuchen (U-148)
  • SM Kapitänleutnant Freiherr von Berkheim (U-149)
  • SM Kapitänleutnant Schneider (U-150)

• Type U 151
  • SM U-151 (ex-SM Oldenburg)
  • SM U-155 (ex-SM Deutschland)
  • SM Bremen (no number before sinking)

{{German Type U 158 submarine|state=expanded}}

• Type U 158
  • SM U-158 through
  • SM U-159 cancelled

• Type U 93
  • SM U-160 through
  • SM U-167
  • SM U-168 through
  • SM U-172 incomplete
  • SM U-162 (later French Pierre Marrast)
  • SM U-166 (later French Jean Roulier)

• Type U 142
  • SM U-173 through
  • SM U-195
  • SM U-196 through
  • SM U-200 cancelled

• Type U 93
  • SM U-201 through
  • SM U-209 incomplete

{{Norwegian A-class submarines|state=expanded}}

• SM U-0 / SM UA (ex-Norwegian A-class submarine HNoMS A-5)

• Type UB I
  • some under Austrian flag
  • SM UB-8 (later Austrian SM U-8, later Bulgarian UB-8)

• Type UB II
  • some under Austrian flag
  • SM UB-26 (later French Roland Morillot)

• Type UB III
  • some under Austrian flag
  • SM UB-94 (later French Trinité-Schillemans)
  • SM UB-99 (later French Carissan)
  • SM UB-125 (later Japanese O-6)
  • SM UB-143 (later Japanese O-7)
  • SM UB-155 (later French Jean Corre)
  • SM UB-156 through
  • SM UB-205 incomplete

• Type UC I
  • some under Austrian flag
  • SM UC-8 (later HNLMS M-1)
  • SM UC-12 (later Austrian SM U-24, later Italian X1)

• Type UC II
  • some under Austrian flag

• Type UC III
  • SM UC-115 through
  • SM UC-138 cancelled
  • SM UC-90 (later Japanese O-4)
  • SM UC-99 (later Japanese O-5)

• Type UD I

{{German Type UF submarine|state=expanded}}

• Type UF
  • SM UF-1 through
  • SM UF-92

• Type UG

{{Bars-class submarine (1915)|state=expanded}} User:Derekbridges/sandbox/Bars-class submarine (1915)

• Type US (ex-Russian Bars class)
  • SM US-1 (ex-Burevestnik)
  • SM US-2 (ex-Orlan)
  • SM US-3 (ex-Utka)
  • SM US-4 (ex-Gagara)

• User:Derekbridges/sandbox/GermanSubTemplates2