Running canasta for 12
For 12 players you will need 3 tables, 6 decks with jokers (2 for each table of 4), and 3 sheets of paper for the score cards (four to a page).
Canasta games are long, so plan a few rounds: one game (or a set number of deals) per round. Partners sit across at a table of 4. At a table of 6, play two teams of three, sitting alternately.
Each score card lists that player's table, partner and opponents for every round. Want names on them, a different number of rounds or a fresh shuffle? Open this chart in the planner.