Work has started on a £60,000 puffin walkway from shops near the Highbury housing estate to Cosham Park, across Portsmouth Road.
Efforts were launched to get the crossing installed in early 2014 because families were worried about the dangers of trying to cross.
The plans never got off the ground at the time.
But money in the council’s traffic fund has now been found to get the crossing up and running.
The only nearby crossing point has been at Cosham railway station, which parents had complained was a long walk. The work is expected to last six weeks and will be done outside of peak times.
Cosham councillor Hannah Hockaday is pleased the authority has taken the action.
Cllr Hockaday, who led the campaign on behalf of residents, said: ‘I’m delighted the crossing is going in, it will make the road safer.
‘I’m happy that after campaigning for it, the crossing is going in, especially as it was a dangerous place to try to get across.’
In a letter to residents, council traffic network engineer Steven Flynn said: ‘During this time it shall be necessary to narrow the width of the road, however traffic will still be able to travel in both directions.
‘There may occasionally be the need to use temporary traffic lights or other measures, but these will only be used during off-peak times to minimise the impact on traffic in the area.
‘We apologise for any inconvenience caused by this work, and hope you will see the benefit of having a new crossing at this location.’
Tory community campaigner Jim Fleming said: ‘Not only is this going to make crossing the road safer, it’s also going to bring Cosham Park into better use because people will have safer and easier access to it – that’s one of the major benefits.
‘There is a park literally across the other side that hardly anyone uses, because people don’t know it’s there as they stick to one side of the road. There’s a corner there as well where some cars go slightly too fast.’