How do I call my friend in Singapore who has a US number?

Singapore’s country code is +65. You should be able to reach your friend by typing 0065, followed by your friend’s number, but minus the zero. If your friends number was,

“0177–5676529”, it would become,

“0065 177 – 5676529”.

Thanks but didn’t work.

If it is a US number, just dial it like normal. The background cell processes should locate his cell (based on his IMEI and phone number) even if it is Singapore. It may take an extra few seconds, but it will find him and ring normally, if it is turned on.

Remember that there is a many-hour time difference,

My suggestion is to email him.

It should work the way it always does with the ten digit number or possibly a 1 in front of the number like here in the US. It’s a US number. Either it’s working or it isn’t, there isn’t a need for prefix like a landline. I call friends and family in Europe and Mexico when they travel, and I just dial like usual. Texting works also. I think they incur additional fees so I feel badly about it, because sometimes I call and I don’t know they are traveling. It probably does not work in all countries, because some cells don’t work I don’t think in certain countries.

Dail 1 and then usual 10 digit number. (or just the usual number) He is likely automatically forwarding his calls.

By the way, give it a few seconds to connect. Also, it will likely ring like the country he is in. I don’t know if Singapore sounds like an American ring? You might mistake an unusual ring for not connecting.

When my husband went to China I could call his cell phone without doing anything extra.

Dial as you normally do, but be aware that your friend may incur international roaming fees which are exorbitantly expensive.

Similar to @jca, I would recommend sending a text in the usual way (instead of an email). The time difference between Singapore and the East Coast of the US is 13 hours in wintertime (Standard Time), and 12 hours during Daylight Savings Time.

Here is a handy tool to coordinate “meeting times” (if you consider that a phone call is a type of meeting) between and among different time zones.

Other than that, the US phone number should work for voice calls, but depending on the carrier and contract, additional charges to the call recipient may apply. That’s another reason to suggest the text: give the other person a reason for why he or she may want to make the connection, and the option to decline if the timing or the reason for the call are not compelling enough for him to accept it right now. (And hopefully if he’s sleeping the text won’t wake him, but that’s on him to manage his phone notifications, etc.)

If your friend has roaming enabled you should be able to dial his number the usual way. If not you’ll need to find out if he is using a Singapore telco. Some cell phones have dual sim card slots so he may have a Singapore number temporarily.