Decades: World Tour (also referred to as Decades: World Tour 2018) was the seventh world tour by Finnish symphonic metal band Nightwish, in support of their seventh compilation album, Decades. The band included a special setlist for this tour, featuring rare songs from the earlier era to revisit with some new twists. The setlist was a 'one-off' and only performed on this tour. It is the final tour to feature longtime bassist/vocalist Marko Hietala who later departed from the band in January 2021.