Reviews » OneSim International SIM cards
One
Sim Card is a product offered by Long Distance Post, LLC, a Massachusetts
based telecom company founded in 1994. Services offered by this company
are available nationwide.
What is an international SIM card?
Most cell phones operate using a SIM card inserted in the back of your cellular device. This card is like a bridge between your cell phone and your wireless carrier. Without it the phone is useless.
The SIM cards from One Sim Card work internationally. This means that, by replacing your current SIM card with the one from One Sim you can place international calls while traveling abroad. This way rates paid will be much lower than what you would pay if you activated roaming service through your current wireless carrier.
Service highlights
Works in 150 countries
No monthly bills, no card expiration date
Free incoming calls
Calls and text messages received are entirely free.
Savings compared to roaming
OneSim claims 85% savings on your calls when compared to roaming charges by major US carriers.
Promo
$10 initial credit.

Three weeks and I had to use my US based ATT phone to make calls.
Word of caution...... These people are a total rip off .... Beware!
Olga the Customer service employee said I must have a bad phone. I told her I purchased it from them and therefore would like to return it. She then said I could not return it as over 30 days had passed. I asked to talk to a supervisor and was told he was to busy. Asked for his name and number and was told I could not have it and he would call me.
Over $25 in unauthorized calls and texts have wiped out my account and they said to bad and denied all responsibility!
This appears to be a company run by Russians and I am almost certain it is less than an honest operation.
I will be filing a report with the Better Business Bureau.
In addition they use an east European country as their base. This means that people calling you have to make an international call. Talking is also delayed like in the old time calls to Europe via the underwater cables. You have to talk - then wait for the message to reach the other party - the other party answers and after a delay you hear what they have to say. if people are not aware of this procedure the conversation gets garbled as people speak over each other's voices. Bad experience - have now purchased T-mobile German prepaid card at 18 cents per call within Germany instead of 59 cents charged by onesim. Am using a land line when i need to make international calls.
However, its does not work on the conventional way. You need to dial the number u want and press the talk(green key) button. Your screen will show "Waiting to connect" and u need to press "OK". You will get an incoming call and you need to answer this call immediately. Then, the system dials gives some announcements like "u have 10 mins left" and connects you to the destination number you dialed decades ago :-)
1 out of 4 attempts gets connected (for me) and on the whole, you end up paying a lot of money. Better use conventional roaming methods with your operator.
I am a professional telecom handset tester and i would not recommend this to my mom !