Long-range antisubmarine:
There are usually anti-submarine helicopters (some have more than one). Helicopters are generally equipped with suspended sonar, sonar buoys and other detection equipment, equipped with torpedoes or deep bombs for long-range anti-submarine. If the submarine is found to be close, use the anti-submarine missile (said upstairs), and if there is no missile, give it to the helicopter.
Short-range antisubmarine:
The anti-submarine torpedo on the ship is in charge. Generally, there are two triplet 324 mm torpedoes (especially in Russia, and some have two quintuple 553 mm torpedoes). If we are closer, we can use anti-submarine rocket depth charges (for example, China's 8 1 is an anti-submarine rocket depth charge launcher, Russia's RBU-2000, which is generally not available in western countries), and this thing can also destroy incoming torpedoes. Finally, some destroyers use depth charges. Finally, anti-submarine depends on it.
Guangzhou class destroyer launches anti-submarine rocket deep-water bomb.