The A30 is a relatively short and very quiet route which heads west from St Johns to Patrick, south of Peel. It starts at a T junction on the A40 to the south of Tynwald Hill and follows Patrick Road past a few houses and into woodland on the banks of the River Neb. Apart from a couple of sharper bends, the route meanders gently through woodland and across fields without passing any road junctions. There are a few bumps, but the route is largely flat. At length, a series of tighter bends leads to a short straight into Patrick, where the route ends at a T junction on the A27.
As originally numbered in the 1920's, the route was given the B25 number, which also included part of the A40. It had been renumbered as the A30 by 1963.