Tomorrow's crossings could also be affected
Both of today's sailings to and from Heysham have been cancelled.
The decision has been made due to adverse weather conditions.
The Steam Packet Company is also warning tomorrow's Manannan crossings are both subject to possible disruption or cancellation.
A decision will be made on whether the sailings will go ahead by 8am tomorrow.
Manx Wildlife Trust: Offshore windfarm ecological assessments 'inadequate'
'We do not agree that such mortality can be insignificant in a Manx context'
"There is a seat for everyone on the Ben-my-Chree"
SPC boss responds to complaints of overcrowding while Manxman is out of action
Diagnosis changed Onchan resident's life 'overnight'
Tia Nicole Murphy is raising money to help get the care she needs for her FND
Village is getting its pub back
The Colby Glen closed suddenly earlier this year