The invention relates to a method for ensuring IP session continuity upon a handover of a mobile node to a non-3GPP network, wherein an ongoing IP session of the mobile node goes via a packet data network gateway. For non-3GPP networks it is necessary to discover a security gateway and to then establish the corresponding tunnels to the ePDG to form the new data path; a security tunnel between the mobile node and the security gateway, and an IP tunnel between the packet data network gateway and the security gateway. In order to prepare the handover to possible non-3GPP accesses, the two tunnels are pre-established, however maintained deactivated until their use is actually needed. Accordingly, when handing over to the non-3GPP network, the IP session may be continued without any significant interruption by activating the already established tunnels.