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).
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