If you're looking to cancel your membership, you may do so within 14 days of purchase for a refund. Please contact Customer Service through this form.
If it's been more than 14 days since you signed up for a Citi Bike annual membership, there is not a way to cancel your account, but you can turn off auto-renew so that your membership expires at the end of your 365-day commitment. To do this, log into your account online and adjust the auto-renew settings.
If you're looking to close your Citi Bike account, please contact Customer Servicethrough this form.