The bridge has been closed on May Day morning since 2005 after 40 people were injured jumping into the river.
Traditionally, thousands of people gather on and around Magdalen Bridge to hear choristers sing hymns at dawn from the tower at Magdalen College.
The city and county councils and police have worked to "ensure a safe" event.
Last year, about 30 revellers ignored safety warnings and broke through barriers to jump from the bridge.
The water is shallow and the county council said the cost to the health service in 2005 was about Â£50,000.
Police urged people not to "abuse" the decision to allow pedestrians access this year.
Many other events will take place across the city, including morris men dancing in Radcliffe Square, Catte Street and Broad Street.
Oxford City Council and the county's cultural development agency, Oxford Inspires, are both working with an event producer responsible for other big occasions in the city.
The leader of Oxford City Council, Councillor Bob Price, said: "We have been working closely with the police and Oxfordshire County Council to ensure a safe and enjoyable event with Magdalen Bridge open, as it has traditionally been, and we are delighted that this collaboration has had a successful outcome."
Oxford commander, Supt Amanda Pearson, said: "Thames Valley Police supports the decision taken by the council to reopen Magdalen Bridge to the public for this year's May Morning celebrations, and will work closely with our partners to ensure this is done in a safe way.
"I would urge people to recognise this decision is one that has been made to further their enjoyment of this unique celebration, and not to abuse it."
Oxford's Magdalen Bridge will be open to the public during the city's traditional May Day celebrations for the first time in six years.