Several thousand people -- many waving the white, blue and red Russian standard or holding flowers -- gathered for a celebratory concert in the city's Nakhimov Square, named after one of Russia's most illustrious admirals.
Shortly after polling closed, exit polls confirmed what spectators never doubted and showed that 93 per cent of voters favoured joining Russia and breaking away from Ukraine.
"We're free of the occupation," shouted Lucia Prokorovna, 60, carrying a giant Russian flag.
Russian rock band Lubeh, known for their patriotic songs, were at the event, drawing a young crowd who cheered as lead singer Igor Matvienko shouted "Hurrah Sevastopol!" and "Success for you!" between songs.
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Samadova Viktorovna, 39, brought along her two children aged 11 and eight to the concert, which was marked by a conspicuous police and security presence plus plenty of alcohol.
"It's magnificent -- look at how many people are here," she said.
The square is a stone's throw from the waters where Russian warships are stationed as part of the Black Sea Fleet -- a constant reminder of Moscow's influence over the city, both past and present.
Sevastopol was founded by Catherine the Great of Russia in 1783 and has been home to the fleet -- a strategically crucial naval unit which provides Moscow with access to the Mediterranean within a day's sailing -- ever since.
It was one of the Crimean War's main battlegrounds and was rebuilt under Joseph Stalin after being destroyed during World War II as German forces held the city under siege.