New York City is included among the new locations.
The membership-based retailer said it will be administering shots "as soon as they are available."
But, being a Costco member doesn't guarantee you'll be able to sign up for the shot.
Costco said it only has a limited number available, and it would follow eligibility guidelines in each state.
"Costco is firmly committed to helping protect the health and safety of our members and employees, and to serving our communities," the company wrote in its announcement.
Manhattan, Brooklyn, Queens and Staten Island stores are set to receive the vaccine once available.
Costco asked its customers to not contact their local store pharmacy to schedule appointments. Instead, customers should visit its website.
The company said they expect to administer primarily Moderna vaccines.
RELATED: Where can you get a COVID-19 vaccine? Tracking availability and progress
RELATED | Vaccine map: See how many vaccines distributed in each NYC ZIP code
NYC vaccine data shows disparity in recipients
MORE CORONAVIRUS COVID-19 COVERAGE
Positive COVID-19 cases by zip code - New York City
New York City COVID-19 Vaccine Tracker
New Jersey COVID-19 Vaccine Tracker
Find out if you are eligible and where you can go to get your vaccine
Do you have coronavirus symptoms?
Where to get tested in New York, New Jersey and Connecticut
WATCH: Eyewitness to a Pandemic
Centers for Disease Control and Prevention on coronavirus
Submit a News Tip or Question