Transportation from London Heathrow International : Heathrow is 15 miles west of central London. (Hotel Shuttles: Dot2Dot  departs from each of the terminals; while HotelHoppa buses serve the hotels in the Heathrow area.) 

The Heathrow Express from allTerminals to London : (All figures are estimates; transfer time does not include time needed to pick up a bag, or if you did not book your flights on one ticket, and your airlines either don't belong to the same Alliance, or do not have a code-share agreement.)
a. From T1 or T2 to:  (a) T3 - walk 10-15-mins;  (b) from T4 or T5  via Heathrow Express, 20 mins - or take the London Underground; 16 mins.
b. From T3 to:  (a) T1 - a 10-min. walk;  (b) T4 or T5  Heathrow Express, 20 mins - or take the London Underground; 16 mins.
c. From T4 to:  (a) T1 or T3 take  Heathrow Express, 20 mins; (b) T5, take Bus 490 or 482; 20 mins.(T4 passengers should change  to the free transfer train to T1, 2 & 3.
d. From T5 to:  (a) T1 or T3 take Heathrow Express to London Paddington, 20 mins, or London Underground; 16 mins.  (b) to T4 take bus 490 or 482;  20 mins.

1. By Train
The Heathrow Express train offers non-stops to London's Paddington station, leaving every 15 minutes from either the 'Heathrow Terminal 5' station or the 'Heathrow Central' station (T1 & T3). The trip takes 15 minutes.
The Heathrow Connect to Paddington -stopping at  five National Rail stations en route, stops at Heathrow Central station (T1 T2 & T3)  - leaves every 30 minutes and takes 25 minutes; with a few minutes more for T4 or T5..
By subway to central London: The London Underground Piccadilly line has four stations serving  all terminals;  The average time to get from T1, T2 & T3 tube stations to Central London is 40-50 minutes.
For Rail & Underground Map & train & railair times - open: www.heathrowairport.com/transport-and-directions/trains.

2. By Bus  The Central Bus Station is between Terminals 1, 2  3, reached within a few minutes (follow signs); it is open 24/7, while the trael center is open 6am-10:30pm. Bagage trolleys are available & an elevator takes you to the ground level . For more bus information open www.tfl.gov.uk/maps/bus)
Buses connecting to Rail Stations: 
  (a) Two RailAir coach lines serve nearby railway stations serving different areas- one at Reading and one at Woking; and
  (b) London Buses to the Feltham station are served by route 285 departing from T1, T2 & T3 and route 490 from T4 & T5.
Other Bus Services:  For West London bus service open ww.tfl.gov.uk  (for route mapss open  www.tflgov.uk/maps/bus)
1. Express Buses: The Green Line route 724 serves Watford, St. Albans & Harlow; London Buses route X26 serves Croydon and Carousel Buses serve High Wycombe.
2. London City Buses, First Berkshire and The Thames Valley serve nearby towns & suburbs.
3. Night bus N9 serves central London during non-operatonal hours of trains.

3. Getting to London Gatwick or Stansted Airports: 
a. to London Gatwick AP:  The National Express coach service offers direct link with up to 6 hourly departures - taking 75 mins. Get tickets at its desk in the Arrivals Halls of the terminals, or onboard the bus.  For more info call 087 781 8181 or visit nationalexpress.com
b. to London Stansted AP:  The National Express coach service departs every 30-60 mins and takes 90 mins.  For more info use the same as to Gatwick).

NEWS:  In June 2013 it was announced that Heathrow is planning for increased connectivity via rail links, which would allow over 70 percent of UK's population to reach Heathrow within 3 hours by public transit & 12M within one hour. Rail capacity is to increase three-fold to 15,000 seats per hour or from 18 to 40 trains per hour.

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