London Underground (Tube) operates a train from Hounslow to Leicester every 5 minutes. Tickets cost $4 - $7 and the journey takes 46 min. East Midlands Trains also services this route hourly. Alternatively, London Buses operates a bus from Hounslow to Leicester every 5 minutes. Tickets cost $3 and the journey takes 35 min. National Express also services this route every 3 hours.
From Hounslow East Underground Station Tube to King's Cross St. Pancras Underground Station, walk to London St Pancras International, then train to Leicester. 2 h 13 min £49. From Hounslow, Grove Road (TW3) line 111 bus to Heathrow Central Bus Station then bus to St Margaret's Bus Station. 3 h 55 min £31. From Hounslow drive to Leicester. 1 h 51 min £21.