What is En Prison in roulette?
En Prison is a French roulette rule that activates when the ball lands on zero. Instead of losing your even-money outside bet outright, it gets locked ‘in prison’ on the table for the next spin. If it wins on the next spin, you get your stake back in full.
How it compares to La Partage
La Partage returns half your stake immediately when zero hits. En Prison keeps the whole stake at risk for one more spin. Statistically both rules have the same effect on the house edge when measured over time — both reduce it from 2.7% to 1.35% on even-money bets. The practical difference is variance: En Prison can result in losing the full stake (if the next spin also misses) or recovering the full stake, whereas La Partage always returns exactly half.
Where to find it
En Prison is less commonly offered than La Partage in modern online casinos. It’s more prevalent in land-based European casinos. Online games labeled as ‘French Roulette’ typically offer La Partage. If both options are available, the choice between them is a personal one based on whether you prefer guaranteed partial recovery or the chance of full recovery.