You can go to Toyosu by trains, Tokyo Monorail and JR Yamanote Line, and subway, Tokyo Metro Yurakucho Line, or bus, Airport Limousine, or Taxi from Haneda International Airport.
It costs 800 Yen by railways and subway. At first get on Tokyo Monorail train and get off Hamamatsucho station, “浜松町” which is the final stop. Then change trains there. Next get on JR Yamanote Line then get off the train at Yurakucho station, “有楽町”. Next get on Tokyo Metro Yurakucho Line subway bound for Shinkiba, “新木場”. Then get of Toyosu station, “豊洲”. It takes around 40 minutes from Haneda airport.
It costs 720 yen by Airport Limousine bus. Get on a bus bound for Toyosu station which is the final stop. That’s all. It takes around 30 minutes.
It costs around 7,000 yen by a taxi and takes around 25 minutes.
Next I’ll introduce how to go to Toyosu from Narita International Airport.