Free WiFi

Register from 3 providers
http://www.ida.gov.sg/Infrastructure/20061027163310.aspx

iCell
M1
SingTel


Quote From M1:

Need Singaore Phone no. for registration

You will receive your password via SMS.
Please note that only local (Singapore) mobile numbers starting with "6", "8" or "9" will be accepted for Wireless@SG registration.

If you are a using a foreign mobile, you can register at the following locations:
1. Customer Service Counters at Changi Airport
2. 31 International Business Park, Creative Resource, #03-03, Singapore 609921. From Monday to Friday (9am to 6pm)

Please bring along valid identification such as your passport or work permit for registration purposes.Thank you.

Airport Customer Service:
Terminal 1

Departure Transit Lounge East and West, Level 2
Arrival Hall Central, Public Area, Level 1
Departure Check-in Hall, in front of Check-in row 8, Public Area, Level 1
To make a report for items misplaced within Terminal 1, you can call (65) 6542 9727.

Terminal 2

Departure Transit Lounge North and South, Level 2
Arrival Hall Central, Public Area, Level 1
To make a report for items misplaced within Terminal 2, you can call (65) 6542 9792.

Terminal 3

Departure Transit Lounge North, South and Central, Level 2
Departure Check-in Hall Central, Public Area, Level 2
Arrival Hall Central, Public Area, Level 1
To make a report for items misplaced within Terminal 3, you can call (65) 6307 8555.

Budget Terminal

Changi Airport Information and Departure CSO Information Counter at Departure Check-in Hall
Arrival CSO Information Counter at Arrival Hall
To make a report for items misplaced within the Budget Terminal, you can call (65) 6543 1713.