No BYO allowed. 2020 CO Senate bill to require 1-bottle BYO for restaurants failed to pass.
You can take an open 750ML bottle home. All open bottles must be stored in trunk of car.
Section 12-47-421, Colorado Revised Statutes allows various categories of sellers (like restaurants) who also sell meals to permit customers to reseal and take with them “one opened container of partially consumed vinous liquor purchased on the premises as long as the original container did not contain more than 750 milliliters of vinous liquor.”
Section 42-4-1305, Colorado Revised Statutes makes it a Class A traffic infraction to consume or have open containers of alcohol in the passenger compartment of a vehicle while on public roads. Penalties for violation include $50 fine plus a $16 surcharge. Open containers must be stored in the trunk. If the vehicle has no trunk, open containers must be stored behind the last row of upright seats.