Quote Originally Posted by scotsfiancee
In my case my dual band phone does not work in HK
It's for another reason as networks are the same in HongKong and in the Philippines. As you can see below, technically a phone working in the Philippines will work in HongKong (and the reverse). A tri-band phone is of no use there. It's useful only if you travel to North or South america.

HongKong: (all these networks are roaming partners of both Globe and Smart)
China Mobile Peoples Telephone Co Ltd: GSM 1800
Hong Kong CSL Limited (HK CSL): GSM 900/1800
Hutchison Telecom (HK) Ltd (3): GSM 900/1800
New World PCS (New World Mobility): GSM 1800
SmarTone Mobile Communications Limited (SmarToneVodafone): GSM 900/1800
SUNDAY Communications Ltd: GSM 1800

Philippines:
Digital Telecommunications Phils, Inc (Digitel Mobile/Sun Cellular): GSM 1800
Globe Telecom: GSM 900/1800
Innove Communications, Inc. (Islacom): GSM 900
Smart Communications Inc (SMART Gold): GSM 900/1800

Are you sure that the roaming was already activated before your travel?