Bus Vannin's advising people not to hang around if they're waiting to get buses around the TT course this morning.
On Facebook, the organisation says delays to today's racing mean its last buses before the closure may be later than previously advertised.
But it says that's not guaranteed - and passengers should get the bus they'd originally planned to make sure they reach spectator spots on time.
It says you can find out more at its information point at Lord Street Bus Station in Douglas.
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