Pakistan's Navy claimed to have spotted an "Indian Navy submarine" in the Arabian Sea on 16 October.
In a press statement on Tuesday, the Navy claimed that its long-range maritime patrol aircraft had "detected and blocked" the vessel "from entering Pakistani waters".
The Inter-Services Public Relations (ISPR), the media wing of the Pakistani Armed Forces, said the Navy had showed "unremitting vigilance and professional competence".
"During the prevailing security milieu, a strict monitoring watch has been kept by Pakistan Navy to safeguard maritime frontiers", the ISPR said.
A previous reported incident occurred in March 2019, while the Pakistan Navy said another such effort took place in November 2016 at the height of the border tensions.
"The recent incident reflects the deplorable Indian machinations vis-à-vis commitment and resolve of Pakistan Navy to defend maritime frontiers of the motherland", the statement added.
The Indian Navy operates submarines fitted with air-independent propulsion systems, which makes detecting the subs much harder.
The Pakistan Navy has been expanding its fleet with the help of China, and Beijing is slated to supply it with eight modified Yuan-class SSKs by 2028.