VPLMN stands for "Visited Public Land Mobile Network". It refers to the mobile network that a subscriber exists in when they are roaming outside of their home network.

In mobile telecommunications, a subscriber's home network is the HPLMN (Home Public Land Mobile Network). When the subscriber travels to a different geographical area and connects to a different mobile network, that network is called the VPLMN (Visited PLMN).

While the subscriber is roaming in the Visited PLMN, he will use its services and resources. Such as making and receiving calls, sending/receiving SMS, and accessing mobile data.

Accordingly, the VPLMN operator charges the subscriber's home network operator for providing service to the roaming subscriber. This occurs depending on the roaming agreement between the two operators.

So that roaming on a VPLMN may incur additional charges on the subscriber, compared to being on the HPLMN.