Bus Vannin says last-minute driver sickness means seven of its services may be called off today.
On Facebook, transport bosses said the affected routes include Douglas to Noble's Hospital, Port Erin, Ballachrink, Willaston and Birch Hill.
The disruption is expected to affect buses between around 4pm and 9pm this evening.
Bus Vannin's apologised to passengers for any inconvenience.
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