Not a lot of people know this, but there is actually a free shuttle bus service operating at NAIA (Manila Int. Airport). I say not a lot of people know this, because no one told me about it, and it took me nearly 2 years to discover it. Before I found out about this, I was either getting ripped of by taxi drivers, or using a substandard private shuttle bus operating outside of the airport. It’s also safer because it transfers you Airside rather than Landside of the airport. This means you drive inside the airport itself instead of driving around the perimeter.
Transfer from T1: When you walk out of T1 having walked through customs, instead of crossing the road into a plethora of people trying to literally take you for a ride, as soon as you exit the doors turn right, stay on the terminal side of the road, ignore all those trying to tempt you into their cars and walk to the end of the building where you will find a small waiting area and hopefully a branded NAIA mini bus waiting to transfer you completely free of charge to your next terminal. When I say completely free of charge, I noticed tipping of P50 going on, and if I have pesos on me I do the same. If I don’t have local currency yet, I don’t.
Transfer from T3 to T1: From the food court on level 4, get in the elevator and choose ground. Walk out of the elevator and look behind you. This is how I first discovered the service. You will see a ‘Terminal Transfer’ sign.
Follow that sign until you come to the transfers desk.
Tell them you want to go to T1 and you will be directed through security (X Ray and Metal Detector) as you are going Airside. You will then find a large waiting area complete with TV. You will be asked for your flight details and when the shuttle arrives you will be called to get on the bus. Once again because the bus operates Airside (within the perimeter of the airport) it is safer and quicker than using the paid services operating outside the airport.