Roads expected to be very busy
It's Mad Sunday, and the roads are expected to be full of bikers, as is tradition, particularly on the Mountain Road.
That's if it can stay open for long enough - it's been shut multiple times daily, and has already been closed this morning.
Later this morning, the Simon Andrews Memorial Lap is taking place, setting off from the TT Grandstand.
It's due to start at 10am, but you're asked to get there well before that and form up in good time.
Police say if you're not taking part, it would be appreciated, and advisable, to avoid this area in the run-up to its start.
Officers will be in attendance to help out, but the event will cause congestion.