Taking place in Stornoway on Lewis from Thursday to Saturday, the festival comes amid one of the busiest times for visits to the islands.
HebCelt's acts this year include Julie Fowlis, King Creosote, Astrid, Runrig and Bella and the Bear.
Early check-ins for ferries has been advised to help ease congestion.
The festival's organisers along with ferry operator Caledonian MacBrayne, Police Scotland, Stornoway Port Authority and islands' local authority Comhairle nan Eilean Siar have jointly issued the advice.
The comhairle said: "We are delighted that so many people are coming to visit the Western Isles for the Hebridean Celtic Festival and various other different events over the coming weeks and we are thoroughly looking forward to welcoming them.
"With ferries at full capacity, we are keen to avoid unnecessary congestion and delays and we would urge passengers travelling by car and by foot, to make sure they check-in early at the ferry terminals.
"Please keep an eye on CalMac social media sites for the very latest service information."
A spokesman added: "It is also essential for those intending to use the bus service between Ullapool and Inverness to pre-book to avoid disappointment."
People travelling to and from the Western Isles have been urged to check-in for ferry sailings early during this week's HebCelt music festival.