There were 2.8 million passengers carried on ferry routes during January to June, with the main operators Caledonian MacBrayne and NorthLink
The UK's ferry industry overall has been buoyed by increasing passenger numbers.
The number of people travelling on Britain's ferry network reached almost 17 million in the first half of this year - a 2.5 per cent rise on the total for January to June 2013.
The figures, from industry body Discover Ferries, follow growth last year when more than 38 million used the network.
Director Bill Gibbons said: "These first half results are very encouraging."