Bencroft Woods near Broxbourne has some nice mountain bike trails, that dry out well
Bengeo Quarry is basically a disused Quarry near Hertford and Bengeo used by mountain bikers.
Betteshanger Park has something for everyone with a large selection of XC trails, BMX Track and trails suitable for all the family.
The Bexley Bike Park, located in Martens Grove Park, Bexleyheath has something for everything, from beginners to those with more experience, including a pump track consisting of a circuit of rollers, banked turns and more.
Bostall Woods is situated in London Borough of Greenwich, and there is something for mountain bikers of all abilities to ride and explore.
Box Steps mountain bike trail is a 200 meter descent over steps, off camber slopes, and around tight switchbacks!!!
Breachwood Mountain Bike Trails are still currently under construction.
The Brighton Level Skatepark is a brand spanking new concrete skate park with a great street flow and lines with various rails, banks and lips & a large bowl.