Sunday night's Steam Packet sailing from Douglas to Heysham (18 November) has been cancelled due to adverse weather conditions.
The scheduled return from Lancashire at 2.15am Monday will therefore not operate either.
The decision's been made ahead of predicted very strong winds in the Irish Sea later tonight.
No decision's yet been made on Monday's Ben-my-Chree sailings.
The company says it will review forecasts and make a final decision on its 8.45 am Isle of Man to Heysham service and the afternoon return, at 7am tomorrow (19 November).
Ard-Shirveishagh hopes he's given members enough time to consider 'Charter for Change'
Live video streaming 'significant step' in making parliament more accessible
Treasury: 'Challenging to justify support for heating oil customers'
Increase of more than 500 patients for mental health services over last 12 months