Although you are not required to wear the armor, wearing the opponent's armor can result in your being accused of being a spy ironically, this dialogue stops once you have joined one side or the other. Even after you are formally inducted, you will have yet one later chance to change sides.
Both sides have an initiation task that you must first complete before you are inducted into the faction. If you have not initiated a quest to join either side, you can simply travel to either base and trigger the quest by speaking to members of the leadership.
To join an army, you need to go to that army's base to join (in Windhelm for the Stormcloaks, or in Solitude for the Imperial Legion). While exploring Skyrim, you will fairly often meet soldiers from both sides, who will ask you to join their side if you have made no choice, or if you belong to the opposite side. If you do make a choice, you can later change sides. You can make a choice to accept the suggestion or you can postpone it. However, this choice only determines which side you will be first asked to join.Īfter escaping the Helgen keep, your chosen companion will suggest that you join their side, adding the corresponding quest to your log.
You are first asked to choose sides shortly after you escape your near-execution and the subsequent dragon attack during the Unbound quest, at the point when you choose whether to enter Helgen Keep with Ralof, a Stormcloak, or with Hadvar, an Imperial soldier. The overall quest arcs for the Imperial Legion and Stormcloaks are similar, and allow you to unlock the same achievements. Either choice allows you to start a series of quests, during which various battles of the Civil War are fought, ultimately resulting in your chosen side taking control of Skyrim. You will be asked to take sides in the Civil War being fought between the Imperial Legion and the Stormcloaks (a historical description of which may be found here).