I would recommend caution with WorldSIM.

My experience was:

The U.K. number provided will not accept any incoming international calls, including those made from their own recommended roaming partner networks.

Their technical department has been working on it for one week, and finally customer service told me that if the WorldSIM card doesn't work it's my problem, and I have to contact each and every one of their roaming partners to ask them to fix the problem with the WorldSIM sim card. They even told me to provide them with feedback from their own roaming partners about the cause of the problem. They also refuse to refund the cost of the faulty WorldSIM card.

Check out other reviews, and note that sites like TrustPilot have remove false positive reviews.

If you need reliability and good service, look elsewhere.