A patrol boat is a relatively small naval vessel generally designed for coastal defence, border security, or law enforcement. There are many designs for patrol boats, and they generally range in size. They may be operated by a nation's navy, coast guard, police, or customs, and may be intended for marine, estuarine, or river environments.
The Japan Coast Guard is the coast guard responsible for the protection of the coastline of Japan under the oversight of the Ministry of Land, Infrastructure, Transport and Tourism. It consists of about 13,700 personnel. The Japan Coast Guard was founded in 1948 as the Maritime Safety Agency and received its current English name in 2000.
The Aso-class patrol vessel is a class of PL type patrol vessel of the Japan Coast Guard. PL stands for Patrol vessel Large, and the class is named after Mount Aso, the largest active volcano in Japan.
Hateruma-class patrol vessel is a class of PL type patrol vessels of the Japan Coast Guard. PL stands for "Patrol vessel Large", and the class name "Hateruma" is named after Hateruma-jima, the southernmost inhabited island of Japan.
The Tsurugi class is a class of small patrol vessel of the Japan Coast Guard (JCG). The development of this class was one of the earliest attempts of the JCG to deal with spy boats from North Korea. In March 1999, the JCG tried to intercept vessels of unknown nationality suspected to be North Korean, but the unknown vessels were too fast, and the Japan Maritime Self-Defense Force had to be called to intercept the unknown vessels. As a consequence of this failure, JCG realized their need for high speed interceptors.
The Korean People's Army Navy or the Korean People's Navy (KPN), is the naval component of the Korean People's Army, the North Korean armed forces.
The Shiretoko-class patrol vessel is a class of PL type patrol vessels of the Japan Coast Guard. PL stands for "Patrol vessel Large", and the class name "Shiretoko" is named after Shiretoko, the northeastern area of the island of Hokkaidō, Japan
The Shikishima-class patrol vessel is a class of PLH type patrol vessels of the Japan Coast Guard. In the official classification, Shikishima and Akitsushima are treated as the only ships in their classes, respectively; and Reimei is treated as the lead ship of her class. The Shikishima class was once the world's largest coast guard vessel until it was surpassed by the Chinese Zhaotou-class patrol cutter in 2015.
The Ojika-class patrol vessel is a class of PL type patrol vessels of the Japan Coast Guard.
The Tsugaru-class patrol vessel is a class of PLH type patrol vessels of the Japan Coast Guard.
The Mizuho-class patrol vessel is a class of PLH type patrol vessels of the Japan Coast Guard.
The Kunigami-class patrol vessel is a class of 1,000 ton-class PL type patrol vessels of the Japan Coast Guard (JCG).
The Iwami-class patrol vessel is a class of 1,000 ton-class PL type patrol vessels of the Japan Coast Guard (JCG).
The Japanese patrol boat Mizuho is a PLH type patrol vessels of the Japan Coast Guard. She is only ship in her class: the construction of a second ship was planned originally, but has not been achieved as of 2020 due to the start of construction of the Shunkō class and Reimei class.
Mizuho (PLH-21) is the lead ship of Mizuho-class patrol vessel of Japanese Coast Guard. She was renamed as Fusō in 2019.
Yashima (PLH-22) is the second ship of Mizuho-class patrol vessel of Japanese Coast Guard.
Akitsushima (PLH-32) is a Akitsushima-class patrol vessel currently operated by the Japanese Coast Guard.
Reimei (PLH-33) is a Reimei-class patrol vessel currently operated by the Japanese Coast Guard.
Akatsuki (PLH-34) is a Reimei-class patrol vessel currently operated by the Japanese Coast Guard.
Asazuki (PLH-35) is a Reimei-class patrol vessel currently operated by the Japanese Coast Guard.
Japan Coast Guard 
