The agency won the account after a competitive pitch against Razorfish, Weapon 7 and TMW.
Aviva previously worked with a number of agencies across its insurance, investment and corporate services, including Albion, CMW, Engage Group and Glue Isobar, before the financial services giant decided to consolidate into a single agency.
Dare will now handle Aviva's consolidated digital account, also covering social media across its life cover and direct services insurance portfolio.
Abbott Mead Vickers BBDO handles Aviva's advertising account, but is unaffected by the appointment.
Separately, Aviva's review of its global business-to-business advertising account is understood to be ongoing. The winning agency will be responsible for the division's press, online and outdoor advertising, and will focus mainly on business-to-business activity, targeting independent financial advisors.