However, there are some restrictions - see the following from their website:
One-Category Upgrade
One-category upgrade requests must be made at the time of booking and apply only for upgrades within the supercategory, depending on availability. Example of a super category upgrade in AquaClass: A2 to A1. Upgrades available from categories 11- A1 on all Celebrity ships except Galapagos voyages.
For sailings departing prior to April 12, 2023: Captain's Club one-category upgrade excludes categories: 12, FV, SV, C1 and Z, Y, X, XC, XA, W. On Celebrity Edge categories 12, 9, 7, 6, IO, 1B, 1A, SV, ES, E1, C2, C1, A1 are also excluded.
For sailings departing on or after April 12, 2023: Captain's Club one-category upgrade excludes categories: IS, ES, SV, SC, PO, DO, DI, DV and Z, Y, X, XC, XA, W.
This offer cannot be used with certain restricted fares including but not limited to Simply Sail, Exciting Deals, Interline, travel agent or employee rates. Upgrades apply for one stateroom per cruise. Stateroom assignments only. Not valid on holiday sailings.
The Captain's Club program terms are subject to change at any time without prior notice. Offers vary by tier, see benefit grid for full details. Captain Club benefits may not be available with other sales and promotions.