By Train:
From London to Eltham:
Trains run from Charing Cross, Waterloo East, London Bridge, Cannon Street and Victoria. You need the ones that say "via Bexleyheath". There are 2 stations that you can use - Eltham and Falconwood, depending on which end of Eltham you want.
From London to Mottingham and New Eltham:
Trains run from Charing Cross, Waterloo East, London Bridge, Cannon Street and Victoria. You need the ones that say "via Sidcup".
Www.national rail.co.uk/
Buses
Eltham is very well served by buses to and from London and has a bus depot attached to Eltham station
www.tfl.gov.uk/tfl/gettingaround/maps/buses/pdf/eltham-2083.pdf
By Road
A2/M2 road link offers direct access to London or through Kent to the coast. The road dissects the inner ring road ( south circular) and outer ring road the M25
The A20/M20 also offers links from London to the coast