The round table group of international shipping associations has reduced the area (HRA) in the Indian Ocean classified as "high risk" for piracy.
Bimco, the International Chamber of Shipping, Intertanko and Intercargo, plus the Oil Companies International Marine Forum (OCIMF), have issued new advice to vessel operators as a result.
The move reflects the ongoing containment of pirate attacks in the region, but a "serious" threat remains, the organisations said.
Correct reporting and vigilance is still crucial, they added.
The reduction of the area takes "full account of recent shipping industry experience, pirate intent and capability and follows extensive consultation with nations, collations and military naval forces, including Combined Maritime Forces, EUNAVFOR and the United Kingdom Maritime Trade Operations (UKMTO), which continue to provide vital advice and protection to shipping," a statement said.
The regional UKHO Maritime Security Chart, Q6099, will be updated from 1 May.
The industry associations said they will continue to monitor developments to the security situation, and will adjust the HRA again if and when the situation warrants it.
Incidents in the region have been cut dramatically in recent years, with West Africa now the latest piracy hot spot.
