The four spans of the bridge have been moved into place over the last week
The Pont y Werin bridge linking Cardiff Bay and Penarth has been completed.
The largest crane in the UK was brought in to move the four spans of the bridge with the final piece being put into place on Thursday.
Cardiff council executive member Cllr Delme Bowen and Vinny Mott of transport charity Sustrans Cymru were the first people to walk across the £5m bridge.
It will officially open to the public in June, linking Penarth and Cardiff's International Sports Village.
The design incorporates a 20 metre opening section to allow river traffic to pass.
Vinny Mott of Sustrans Cymru and Cllr Delme Bowen were first to walk across the bridge
The bridge will also provide the final link completing the six-and-a-half mile (10.5km) circular Bay Edge Walkway and cycle route and connect it into the Vale of Glamorgan.
Cllr Bowen, Cardiff council's executive member for transport and transportation, said: "I am honoured to be one of the first to walk across the bridge; a lot of hardwork has gone into bringing Pont y Werin to life.
"We have received an overwhelming amount of support from the Cardiff and Vale communities, who I know are looking forward to the bridge opening in June.
"Pont y Werin will make a huge difference to both communities and will complete the bay edge walkway."
Funding for the new bridge has come from the Welsh Assembly Government, Sustrans, the Cardiff Harbour Authority, along with Cardiff and Vale of Glamorgan councils.
Sustrans is using a £50m grant from the Big Lottery Fund to create new walking and cycling routes across the UK to connect communities and help people make more local, everyday journeys by foot or by bike.
Vinny Mott, Senior Project Manager for Sustrans Cymru, said: "It's great to see the bridge in place - it will provide a vital link between Cardiff and Penarth.
"We can't wait for it to be open later this year so that local people can start using it to get across the river safely, by foot and by bike, away from the roads and the jams."