AccessRoad access is from the roundabout at the junction of the A27 (continuation of M27 from the west of A3M from the north) and the A3020 Portsmouth Eastern Road (marked for Southsea from the A27). The entrance opens off the south east quadrant of the roundabout and is difficult to negotiate because it is not sign-posted and there is usually a lot of traffic going to Portsmouth which does not expect you to turn into it. Make sure you are in the nearside line and going slowly as you pass the slip road coming to the roundabout from the westbound A27, prepared to make a sudden sharp left turn half way between the A27 slip road and the Eastern Road.
ParkingDo not park in the carpark immediately inside the entrance but drive eastward along the roadway to the carpark marked "A" on the map, immediately before the reserve gate prevents you going further. (If all spaces are occupied you can turn in the gateway area and go back to first available place).
Restricted areasAt the reserve gate there is a notice board with map and latest sightings. My rough map indicates footpaths by dashed red lines, areas in which you can walk freely are filled in green and the no-go areas are filled in yellow.
Time requiredI suggest you first walk south down the seawall to the lake (best viewed from the seawall). If you decide to continue along the seawall around the reserve be aware that it is a 4 km circuit to return to the carpark (far longer if you go on to explore all of the reserve north of the A27) and it will take you more than an hour at birding speed (allow an hour and a half).
At the lakeFrom the seawall above the lake (marked "C" on the map) you will see the stream with its reedbeds stretching ahead of you to the north east. To the left of the stream is the open access area known as "The Bushes" in which you can expect to see passerines and to get views of waders, waterfowl and perhaps Bearded Tits along the stream (please do not approach the stream closer than the line of white posts - if you do you will endanger ground nesting birds in the spring and disturb the birds along the stream at all times, making you very unpopular!). To the right of the stream is the large "Main Marsh" to which there is no access but on which you can view roosting waders at high tide, geese and ducks at any time in the winter, and breeding Lapwing in the summer. Behind you is the area of the harbour known as "Shutt's Lake" (the channel taking water away from the reserve lake) and beyond that is "Broom Lake" (the main channel which goes under the Eastern Road bridge and serves Kendall's Wharf a little south of you).
The south wallWalking south the seawall takes you along the south of the main marsh, and from here as you look north alongside the reedbeds you will get a distant view of the "Scrape" area. South of the wall is a small island called "Little Binness", and to the north of the wall is a small pond marked as "Seamus Pond" on the OS map but known more commonly as the "Willow Pool" though the willow tree overhanging it is now dead - you are unlikely to see anything more than rabbits around it.
The PointApproaching "The Point" (marked "D" on my map) you come to the "Point Field" which is open access, but boggy and at times mostly underwater. This is a favourite place for Short Eared Owl in the winter and Yellow Wagtail in the summer. Dartford Warbler have spent the winter here on occasions. The Point gives you the best views south, while in the foreground you have a small circular stony island (the remains of where a house once stood, getting its water from a well down into the chalk below the harbour) - this island can be packed with waders at high tide.
The east wallWalking north up the eastern seawall you have the channel known as "Russell's Lake" on your right, and this brings Merganser, Goldeneye and other wildfowl within reasonable distance. When the tide is down there are waders on the near side of the channel and the RSPB islands in the background. On your left you soon come to "The Deeps" which offer a second lake for close viewing , though parts of the water are out of sight in winding channels. Continuing north you come to North Binness island on your right (no access to the RSPB Islands) and to the first opportunity to take a path inland. If you decide not to turn left on this path the seawall takes you to the A27 where you can either leave the reserve and head east along the Solent Way footpath to the Havant area (Broadmarsh and the Langstone South Moors) or can take a path west across the field nearest the A27 (known as the "Slip Field") then turn south to rejoin the route back to the carpark.
Route optionsIf you decide to take the first path west it will bring you to a junction where you can turn north to access the "Slip Field" south of the A27 or go under the main road into the substantial area north of the road (ponds, bushes and grazing meadows). If you continue west you come to the "Reserve Building" in which an open porch gives some shelter from the weather and has a bench seat under another 'sightings board'. The building is a store place and workshop for the reserve warden (Bob Chapman - you may also meet assistant wardens including Chris Cockburn or Terry Jennings as you go round) and you will notice that it gets its electricity from the wind).
The BushesOpposite the reserve building are gates giving access to The Bushes and the stream area and most people wander through here on the way back to the cars but if in a hurry the unmade road alongside the A27 will take you there with the minimum of delay or uncertainty as to the route.
North of the A27If you decide to explore north of the road (best in the summer) go under the A27 and turn left off the 'road' to Peter's Pond, then head north past the original reserve pond (now very overgrown) to the path which takes you left to the springs (visibly bubbling up into the stream). This path is a dead end but if you go back along it you can make a circuit first alongside the railway through trees and open areas until you come to the west end of a long thin triangular grazing field (no point in going far along it as it is a dead end). Either here or a little way back you will find a viable path taking you south to return along a path and across a field alongside the A27.