In almost any case, the quickest type of divorce you can get is an uncontested divorce. This is a situation in which both spouses agree on all major issues, such as division of assets, child custody, and support payments, without needing to go to trial. They can come to this agreement on their own or through previous mediation.
Since there's no disagreement to resolve during the actual divorce proceedings, the process can move swiftly, sometimes resolving in as little as a few weeks.