Haneda Airport has three terminals connected by free shuttle bus service:
International Terminal
Domestic Terminal 1
Domestic Terminal 2
Free shuttle buses stop on the ground level in front of each terminal.
You can walk between domestic terminals 1 and 2 in several minutes
The international terminal is far from domestic terminals, so you need to take the free shuttle bus.
Keikyu Line train stations
Keikyu Line has two stations at Haneda Airport:
"Haneda Airport International Terminal" station
"Haneda Airport Domestic Terminal" station
You can buy a PASMO (prepaid IC card) from a Keikyu Line ticket machine.
Tokyo Monorail stations
Tokyo Monorail Line has three stations at Haneda Airport:
"Haneda Airport International Terminal" station
"Haneda Airport Domestic Terminal 1" station
"Haneda Airport Domestic Terminal 2" station
Unlike Keikyu Line, Monorail Line has a station at each of Domestic Terminals 1 and 2.
You can also buy a 'Monorail SUICA (prepaid IC card)' from a ticket machine at any Keikyu station at Haneda airport.
Monorail SUICA is 100% compatible with SUICA and PASMO, but you can get a deposit refund only at some Monorail stations for a fee.