"AS PART OF ONGOING OPERATION SAMUDRAGUPTA 2022-23 [pin symbol] Approx 2500kg high purity Methamphetamine seized [pin symbol] From Indian waters off Kerala," the bureau tweeted on Saturday.
The body also said that one Pakistani national was detained among other suspects.
The NCB conducted the operation together with the Indian navy. Its aim is to stop maritime trafficking of drugs originating from the so-called "Golden Crescent," which includes territories of illegal drugs production in Afghanistan, Iran and Pakistan.
A navy intelligence unit received information about a "carrier ship" with drugs on board, which left a port in the Pakistani province of Balochistan, according to the NCB.
"The constant collection and analysis of intelligence allowed to identify a very likely route along which the carrier ship could carry out smuggling. An Indian navy ship was deployed near the "Golden Crescent." Based on this data, the navy intercepted a large sea vessel. Methamphetamine hidden in 134 bags was seized from the ship," the bureau said.
In total, around 3,200 kilograms of methamphetamine, 500 kilograms of heroin and 529 kilograms of hashish were seized during the Samudragupta operation, according to the NCB. The bureau believes the last batch of drugs came from Afghanistan and was planned to distribute in India, Sri Lanka and the Maldives.