It depends on the reward. Ticket track rewards unlock as you play, leaderboard rewards are sent when the leaderboard closes, and Crew track rewards you didn't claim are sent to your Gifts when the event ends. Task rewards are different: you have to claim them yourself before the event ends.
When does each reward arrive?
The timings below are for 7-day events, where the leaderboard closes on day 5.
Ticket track. Each reward unlocks as soon as you reach its Ticket goal.
Bonus track. Offered in some events for the last days, after the leaderboard closes.
Premium track. If you bought it, its rewards unlock as you reach each tier.
Crew Progression Track. You claim these yourself. Anything you could claim but didn't is sent to your Gifts when you leave the Crew or when the event ends. See How do I claim Crew Progression Track rewards?
Leaderboard rewards (individual, Crew, and leagues). Sent to the Gifts section of your Inbox after the leaderboard closes. They go out in batches, so give them a little time and reopen Highrise.
Minigame league rewards (such as Pachinko or Dice Fight). Sent the day after the event ends.
Event tasks. Claim each one in the event before it ends. Unclaimed task rewards expire, and Support can't add them afterward.
Can I trade my event rewards?
Items that give an event Boost are locked until the event ends, then become tradable. While the event runs, they show as not eligible for trading. That's expected.
Leaderboard rewards are tradable as soon as they arrive.
Some rewards, such as premium track rewards, are account-bound and never become tradable. An item's details show whether it can be traded.
Grab items you spun with Bubbles or Promo Tokens are account-bound copies.
For how trade locks work in general, see Why does my item say Locked or "Tradable in"?
Why are the rewards different from last time?
Reward mixes change from event to event on purpose, including which items are in the leagues, leaderboards, and tracks. Reward tiers are set for each event and aren't changed on request.
Still need help?
If a reward hasn't arrived by the times above, follow I didn't get my event rewards. What should I do?.