MV Isle of Arran (Scottish Gaelic: Eilean Arainn) is a drive-through ferry operated on the west coast of Scotland by Caledonian MacBrayne.

Also known by her local nicknames IOA and The Auld Trooper, she entered service in 1984 on the Ardrossan to Brodick route, serving Arran for nine years before being moved to Kennacraig.

In 1993, less than ten years after her launch, she was replaced by the larger MV Caledonian Isles and left to take up the Kennacraig to Islay crossings.

On Wednesdays during high summer, her roster took her past Port Askaig to Colonsay and Oban, returning to Kennacraig after dark.

The winter months saw Claymore or Iona relieving at Islay while Isle of Arran covered for the other large vessels at Oban, Ardrossan, Ullapool and Uig.

In this role, Isle of Arran was able to improve several routes, carrying out additional sailings on a new roster incorporating runs to Colonsay, Coll, Tiree, Barra, South Uist and Mull.

This arrangement doubled capacity on the route, and Islay could still be served on Wednesdays while Hebridean Isles sailed to Colonsay and Oban.

Prior to the 2004 season, she spent time in the James Watt Dock undergoing major work to replace her car deck.

[6] In July and August 2012, she operated the additional services alongside Caledonian Isles, a role filled by MV Saturn until the previous summer.

During September 2012, she provided temporary cover on the Rothesay - Wemyss Bay service whilst MV Bute underwent engine repairs.

[citation needed] In August 2015, it was announced that Isle of Arran would be replaced in 2018 by MV Glen Sannox, one of two new ferries being built at Ferguson Marine Engineering at Port Glasgow on the Clyde.

[13] After covering at Islay, she provided extra Easter sailings to Arran, but after she resumed her regular summer timetable, she developed a propeller fault, leaving her out of service for nearly two weeks.

In November 2017, Isle of Arran assisted Hebrides by taking some Lochboisdale-Uig sailings while the Lochmaddy linkspan was being repaired.

During February and March 2018, she suffered issues with her propeller shafts while covering for Hebridean Isles on the Islay run and was out of service for approximately two weeks.

[16] In August 2018, Isle of Arran suffered further issues with her propeller shaft and was out of service for approximately two weeks while repairs were carried out at Garvel Dry Dock.

She subsequently took up her regular post as second vessel on the Ardrossan - Brodick route, but was limited to carrying only 79 passengers due to social distancing.

The rest of the year saw no change in her usual schedule, with her annual inspection carried out from late September until mid-October before she relieved other vessels.

She only lasted a few weeks before swapping with MV Hebridean Isles on the Islay run due to stabiliser issues, meaning she had to head for more sheltered waters.

During this period, the start of her season on the secondary Arran roster was delayed, but she eventually took up service on the route in early June.

MV Loch Riddon was deployed to run alongside Catriona between Claonaig and Lochranza to provide additional capacity.

[23] Caledonian Isles experienced delays during her annual overhaul and was eventually removed from service for steelwork repairs.

After which, she was redeployed to Oban to cover other vessels on the CalMac network after the introduction of MV Glen Sannox on the Troon - Brodick route.