Two out of five Japanese submarines actually made it into Pearl Harbor
The Type A Ko-hyoteki class was a special class of Japanese midget submarines operated by the Imperial Japanese Navy during the Pacific War. The submarines formed part of the secret weapons of the Imperial Japanese Navy and, therefore, they did not have own names. They were often called by the hull number of the mother submarine. Thus, the midget transported by I-19-class submarine was known as I-19’s boat, or “I-19tou”. Tou means “tokubetsu” (special)
During the special attack on Pearl Harbor, five of these boats tried to enter into the Pearl Habor bay. Two actually made it into the harbor.
The hull numbers of these midget submarines indicate that at least five I-class submarines, I-19, I-18, I-20, I-22 and I-16 were involved in the operation.
A 1/700 scale model of the I-19 submarine and the US Navy Wasp carrier.
First one: no.19 midget submarine
No.19 was captured with its pilot Kazuo Sakamaki where it grounded on the east side of Oahu.
Second one: no.18 midget submarine
A second Pearl Harbor midget submarine, No.18, was located by U.S. Navy divers off Keehi Lagoon east of the Pearl Harbor entrance on 13 June 1960.
Third one: no. 20 midget submarine
The third midget submarine was attacked by Ward (DD-139) at 6:37 a.m. on 7 December. This midget submarine No.20, was located in 400 meters of water five miles outside Pearl Harbor. This research was conducted by the University of Hawaii using a special research submersible on August 2002. More recently, another visit was performed by a Okeanos explorer ROV, on the 7th of December 2016, 75 years after it was sunk. The footage corresponding to that research is at the bottom of the page provided by Youtube channel of ABC news.
Fourth one: no. 22 midget submarine
A fourth submarine, No.22, entered the harbor and fired its torpedoes at Curtiss (AV-4) and Monaghan (DD-354). In this attack, both of those torpedoes did not hit the targets. Some sources indicate that the torpedoes might have hit a dock at Pearl City and the shore of Ford Island. Eventually, the submarine was sunk by Monaghan at 8:43 a.m. on 7 December.
Fifth one: no. 16 midget submarine
In 2009, a combined research team organised by PBS Nova successfully identified the remains of the fifth midget sub. She was found outside the Pearl Harbor entrance. Her name corresponded to the no.16, the fifth Ko-Hyoteki midget submarine that participated in the attack. It was discovered in salvage from the wreckage of the West Loch Disaster of 1944, dumped three miles south of Pearl Harbor. It is believed the fifth sub successfully entered Pearl, fired on Battleship Row, and escaped to the relative quiet of neighboring West Loch, where it was scuttled by the crew. Secret documents of the imperial Japanese Navy revealed that this was the orders they gave to the crew. First, fire againts targets and after that scuttle the submarine in a secure location.
See here the link with 1st Live Streamed of the Japanese submarine that never made it to Pearl Harbor. Video material is from NOAA and provided in Youtube by ABC News as follows:
1/700 Japanese Navy Mutsuki-class destroyer Kisaragi + midget submarine by Pit lord. Note the small size of the midget submarine compared to the destroyer.