A £3.5m bridge linking Cardiff Bay to Penarth could be built within the next few years.
The bridge will span from Penarth to the sports village
Cardiff Council say they have reached agreement about funding for the 140m (459ft) bridge, which could see Big Lottery Fund money used.
The project will be one of several competing for a grant from the fund's "living landmarks" competition.
The bridge across the River Ely would be for pedestrians and cyclists and would open for river traffic.
The council has been working with sustainable transport charity Sustrans to try and identify sources of funding for the scheme.
The winner of the lottery cash will be decided by a public TV vote later this year. It is thought the grant could be worth about £1.15m
The Harbour Authority has already carried out a feasibility study, with land allocated on both sides of the river for a bridge, which would link Penarth with the International Sports Village.
Cardiff Council leaders say the bridge is a high priority.
Lee Waters, from Sustrans, said: "This bridge makes such a necessary link that it will change many people's mental maps of their local area.
"It will make cycling and walking much safer and more enjoyable and is a great opportunity to improve sustainable transport links in the area to the benefit of all."