Piracy attacks and armed robbery attempts against vessels have fallen 14% in the first nine months of 2017.
The International Maritime Bureau (IMB) said there had been 121 incidents to 30 September, down from 141 in the same period of 2016.
"While piracy rates were down...there is continuing concern over attacks in the Gulf of Guinea and in South East Asia," it added.
It also mentioned Libya, where an attempted boarding took place in the last quarter, as an area that requires vigilance.
In total, 92 vessels were boarded, 13 were fired on, there were 11 attempted attacks and five ships were hijacked.
No incidents were reported off the coast of Somalia in the third quarter.
But IMB said: "Successful attacks from earlier in the year suggest that pirates in the area retain the capacity to target merchant shipping at distances from the coastline."
International maritime charity Sailors’ Society said fear of piracy remains a "massive issue" for seafarers.
It has set up three crisis response networks in Africa, Asia and Europe to support survivors of attacks.
CEO Stuart Rivers said: "While we are encouraged that incidents of piracy are generally decreasing, piracy is a still a major concern and any incident is one too many.
“Survivors of piracy and kidnappings are exposed to violence and terror, which can have a devastating impact on them and their families for years to come.
“By coming alongside these survivors and their families, we can work with other agencies to help them come to terms with what has happened and give them financial, physical and psychological support to help them pick up the pieces of their lives.”
Malaysia’s success story
IMB said one vessel was reported hijacked in the third quarter when a Thai product tanker was attacked off Pulau Yu in Malaysia in early September.
"But thanks to the prompt intervention of the Malaysian Maritime Enforcement Agency, 10 hijackers were successfully apprehended and the tanker was safely escorted to a nearby port," it added.
“The Malaysian response demonstrates exactly the type of speedy and robust action that is needed to deter such attacks,” said IMB director Pottengal Mukundan.
In Nigeria, a total of 20 reports against all vessel types were received. Of the 49 crew kidnapped globally, 39 were taken off Nigeria.
“In general, all waters in and off Nigeria remain risky, despite intervention in some cases by the Nigerian navy. We advise vessels to be vigilant,” said Mukundan.
“The number of attacks in the Gulf of Guinea could be even higher than our figures as many incidents continue to be unreported.”
Venezuelan violence
Venezuelan incidents have risen to 11 from three in 2016.
All vessels were successfully boarded by robbers armed with guns or knives and mostly took place at anchorage. Four crewmembers were taken hostage during these incidents, with two assaulted and one injured.
The IMB highlighted the importance of its 24-hour manned piracy reporting centre (PRC), which provided the maritime industry, governments and response agencies with "timely and transparent data on piracy and armed robbery incidents received directly from the vessels or owners, flag states or navies."
Its prompt forwarding of reports and liaison with response agencies has helped keep seafarers safe, it said.
“One of the strongest weapons triggering the fight against piracy is accurate statistics,” said Mukundan.
“There should be free and reciprocal sharing of information between the IMB PRC and regional information centres. With a clearer picture of when and where violent incidents are taking place, authorities are able to better allocate their resources to tackle this global issue.”