In accordance with an embodiment, described herein is a system and method for partition migration in a multitenant application server environment. Each resource group, or partition which includes that resource group, can be associated with a virtual target (e.g., virtual host) information that defines a target to which that resource group or partition should be targeted and deployed. A web tier component (e.g., Oracle Traffic Director) includes a routing information, which maps the virtual target for a partition to a corresponding target such as a server or cluster, so that requests for that partition are directed to the appropriate target, for example as part of one or more sessions. When a partition is migrated, session information is replicated between an original target and a new target, and the web tier component provided with a revised routing information, so that subsequent requests for that partition are directed to the new target.