Bus Vannin says its services in the west of the island will divert around roadworks on the TT course which are due to start today.
The Department of Infrastructure is doing work to improve drainage at Creg Willey's Hill in time for this year's racing.
It means the course will shut between Ballig Bridge and Cronk y Voddy from 9.30am today.
Isle of Man Transport says its buses will divert via Poortown Road and Knocksharry to Kirk Michael.
Island could get thunder tonight
Hospitality firms owe £2.8 million in VAT
Minister: avoid cheap homemade drinks when abroad
Dogs to be welcomed onto Douglas beach all year round?
Man who walked across America plans Manx challenge
Landmark bridge to open to pedestrians during repair works
Tributes paid to North Douglas MHK
Chance to see solar eclipse next week