From Pireaus:

By high-speed ferry from Pireus harbour in 2-4 hours.
Pireaus Port Tel: +30 210 35.30.000
Milos Port Tel: +30 22870 23.360

From Athens:

By plane from Athens International Airport in 40 min.
Athens Airport Tel: +30 210 35.30.000
Milos Airport Tel: +30 22870 23360