This is the first part of the route to Portsmouth (see below for the rest of the route):
We suggest you use the west side of the bridge because it gives you shared pedestrian/cycle route all the way from the top of the Billy Trail to where the trail emerges at Langstone Road (the red section of the route).
From there the route goes along Langstone Road to the entrance to Langstone Technology park. The pavement on the west side of the road is a shared cycle path.
Having entered the road that leads to Langstone Technology Park, go past the Langbrook Farm restaurant and you will see a footpath (not a cycle path) on the right that takes you alongside the river to a shared path that starts at the corner of the Langstone Technology Car Park and continues west alongside (but not in) the car park until it emerges onto Harts Farm Way. Turn right (west) and cross the road to join the cycle lane and continue west.
Many cyclists continue past the footpath next to the river and take the next right turn into the car park in front of the first LTP building. You can then cycle to meet the shared path at the opposite corner of the car park. The car park is private but the owners seem to take a benign view of pedestrians and cyclists using it as a cut-through as long as they take care and do not cause a nuisance. We understand that allowing pedestrians and cyclists to use the car park was a condition of the original planning consent. This route is shown in green on the map.
This is the route along Harts Farm Way to the start of Farlington Marshes (click the image to see a larger version):
The section to the first roundabout is a cycle lane. After that, the entire route uses a shared pedestrian/cycle path. Just take care when passing entrances that cross the path.
This is a popular cycle route so be aware of the possibility of cyclists in front and behind.
This is the shared pedestrian/cycle path across Farlington Marshes to the big roundabout at the junction of the A27 and Eastern Road:
Again, please take care because this is a popular cycle route with an excellent surface so look out for pedestrians and beware of cyclists from in front and behind.
The blue route shows the route to the east of Portsmouth which takes you to the seafront and NCN route 2 into Portsmouth. There is a shared pedestrian/cycle path all the way down the Eastern Road. This is the best route to get to the Isle of Wight ferry terminal at Gunwharf Quays.
This is an alternative route to the west of Portsmouth and a quieter route to the international ferry terminal via the Hilsea Lines.
Note that the route requires you to get through two kissing gates which will be difficult for tandems and trikes. The easiest way to get bikes through is to dismount and push your bike through rear end first.
Portsmouth City Council publishes a map here showing routes to Portsmouth via Eastern Road and Hilsea Lines. Note, however, that from April 2017 for three years, the cycle path along Tipner lake will be closed during late spring and summer months for flood defence work. You will instead be redirected to a temporary cycle path along Northern Parade.