The Steam Packet company says the Ben my Chree will arrive in Douglas later than usual this evening.
It says bad weather is to blame for the delay, which means the vessel won't reach the Island's capital until 7.30pm.
That will mean tonight's return crossing will also be behind schedule and leave an hour late at 8.45pm.
Passengers are being asked to check in no later than 8.15pm.
Warning over parking suspensions for King's visit
Peel residents outraged over toxic powder spread near young gull
Commissioners tackle beach rubbish after online criticism
This year's bookings will be honoured, says closing venue
Noel tackles charity car wash for Autism Initiatives
TT legend's bike could fetch up to £55k at auction
Southern road temporarily closed this week
Number registered with GPs has risen by 1.7 percent