Captain, crew and passengers aboard P&O Ferries will take part in their third annual 'Ocean Watch' survey, which aims to raise awareness of Irish Sea wildlife.
The whale and dolphin conservation charity are training P&O Ferry Captains and the entire crew on board who travel from Larne to Cairnryan how to identify different marine species.
They will also train staff on how to collect vital data for the project, which will help inform ORCA of the population levels of whales and dolphins in the region, collectively known as 'cetaceans'.
The number of animals counted by crew in last year's survey - including a bottlenose dolphin.
Non-cetaceans spotted will also be recorded, including seals, sharks, tuna and large fish.
This year ORCA Wildlife Officers will travel on-board selected sailings on Sunday 29 July to help passengers enjoy some successful spotting.
In last year's survey, crew counted more than 25 animals spanning the harbour, including a bottlenose dolphin, Risso's dolphin and an unidentified whale.