The shinkansen from Shin-Osaka Station covers the 330 kilometres to Hiroshima in 90 minutes, making a day trip to Hiroshima and Miyajima from Osaka one of western Japan's most efficient dual-site itineraries. Hiroshima Peace Memorial Park occupies 122,000 square metres along the Ōta River delta, centred on the Genbaku Dome — the only structure left standing within the 1945 hypocentre's two-kilometre radius. The dome's skeletal frame, preserved in its August 6 state, anchors a park corridor that includes Kenzō Tange's 1955 cenotaph, the Children's Peace Monument, and the museum at 1-2 Nakajima-cho, which opens daily at 07:30. Miyajima lies 40 minutes southwest of Hiroshima by JR ferry from Miyajimaguchi Station. The island's formal name, Itsukushima, predates its shrine by centuries; the current vermilion torii, rebuilt in 1875, stands 16 metres tall in the tidal flats and floods twice daily with the Seto Inland Sea. The shrine complex behind it, first constructed in 593 and rebuilt in 1168, floats on pillars during high tide. The corridors cover 280 metres of interconnected platforms, designed to flex with tidal pressure rather than resist it. Day trip to Hiroshima and Miyajima from Osaka tours typically allocate two hours at the Peace Memorial site and three on Miyajima, with 90 minutes reserved for shinkansen transit each direction. The bullet train departs Shin-Osaka between 07:00 and 08:30 for same-day return by 20:00. Guided options include lunch at Miyajima's covered market or vegetarian thali service near the shrine, while independent travellers use the JR Sanyo Pass for flexible ferry timing. The museum's main exhibition spans two floors and 2,200 square metres, holding 21,000 artefacts. August remains the busiest visitation month; November through February see the lightest crowds and the clearest views of Mount Misen's 535-metre summit from the shrine deck. The torii's low-tide window occurs twice daily, allowing visitors to walk to its base and examine the camphor wood pillars up close.