There are several ways to get from Hiroshima to Miyajima and back. We decided to go over by the new-as-of-August-2016 World Heritage Route boat and return via ferry and train. Both options worked smoothly and there wasn’t a lot of difference in the total time for us. The boat is more expensive, but also more scenic and requires no connections once you board at the Peace Park.
The World Heritage Route boat leaves every 45 minutes starting at 8am from a dock just across the river from the Peace Park by the first bridge just south of the A-Bomb Dome. The cost is 2000 yen per adult, one-way or 3600 yen, round-trip. The boat is enclosed and air-conditioned and drops you off at a dock a short distance from the ferry dock on Miyajima.