In Arad, near the Bahrain International Airport, there is a very pleasant off-road run around the Dohat Arad Lagoon and the Arad Fort Beach Park. There are three sections to this run: The signature piece is the 3 km loop around the lagoon in Dohat Arad Park. This paved path with distance markers has views of the water the whole way and several nice green spaces.
For more, cross Highway 21 to the path along Arad Fort Beach Park (use Avenue 40). It’s a 2 km out and back to Arad Fort. Then, run along a pleasant path paralleling the Khalifa Al Khabeer Highway, to the Derby Cafe/Beach Pavillion. It’s a ~2 km out and back. So, this route is 4 km overall, or 7+ km if combined with the lagoon loop.