In 2026, seeing all of Universal Studios Hollywood in one day is entirely possible, but it requires a strategic approach. Unlike its massive counterpart in Florida, the California park is built on a more compact footprint across two levels (the Upper and Lower Lots). To "see it all," including the world-famous Studio Tour and the immersive SUPER NINTENDO WORLD, you must arrive at least 30 minutes before opening and utilize the mobile app for real-time wait tracking. For a guaranteed "one-day completion," the Universal Express Pass is almost mandatory in 2026, as it significantly reduces wait times for top-tier attractions like Harry Potter and the Forbidden Journey and Mario Kart: Bowser’s Challenge. If you are visiting during peak summer or holiday windows, a single day without Express may force you to skip several shows or smaller rides. However, with the right planning—starting in the Lower Lot and ending with the Studio Tour in the late afternoon—you can successfully experience every major attraction before the park closes.