The parks say each one needs 6 to 7 hours to cover its rides and experiences, and Ferrari World, Warner Bros. World and Yas Waterworld do not allow re-entry once you leave. Two parks in one day means rushing both.
For two parks or more, look at the official Multi-Park Experience: two, three or all four parks, with 6 days after your first visit to use the rest. Yas Island says it saves AED 200 to 700, depending on how many parks you choose. Entry is by FacePass or fingerprint; if you opt out, everyone needs official photo ID on every visit.
We sell single-park tickets for all four parks. For one park, compare the two prices on each card above; for two or more, set the official pass against the total of our single tickets before you buy.