Kaidai-type submarine
| Class overview | |
|---|---|
| Name | Kaidai-type submarine | 
| Builders | |
| Operators | Imperial Japanese Navy | 
| Subclasses | 
 | 
| Built | 1921–1943 | 
| In commission | 1924–1945 | 
The Kaidai-type submarine (海大型潜水艦, Kaidai-gata sensuikan) was a type of first-class submarine operated by the Imperial Japanese Navy (IJN) before and during World War II. The type name was shortened to Kaigun-shiki Ōgata Sensuikan (海軍式大型潜水艦) Navy Large Type Submarine.
All Kaidai-class submarines originally had a two-digit boat name, from I-51 onwards. On 20 May 1942, all Kaidai submarines added a '1' to their names. For example, I-52 became I-152. Ships are listed by the three-digit boat name if they had one, two-digit if they were not granted one or left service before 20 May 1942.