Yes. Kalshi operates fully in California, sports contracts included, and so do Polymarket US and Novig. California has never legalised sports betting (voters rejected two measures in 2022), which makes it the largest market in the country where a prediction market is the only regulated way to trade on a game. That's also why California tribes sued under federal gaming law. A federal judge denied their request to block the markets, but on September 16, 2026 a unanimous Ninth Circuit panel reversed, holding that Blue Lake Rancheria and Chicken Ranch Rancheria are likely to succeed on their claim that Kalshi's sports contracts on their tribal lands violate the Indian Gaming Regulatory Act. The case is back in district court to decide on an injunction. Status as of October 15, 2026.
What's available
| Platform | Status in California | Age |
|---|---|---|
| Kalshi | All markets, including sports and combos | 18 |
| Polymarket US | Available via the app | 18 |
| Novig | Available (not one of its three excluded states) | 21 |
| Robinhood / DraftKings / FanDuel prediction products | Available | 18 |
The legal picture
Unlike Nevada, Michigan or Massachusetts, the State of California has not sued Kalshi or sent a cease-and-desist. The challenge comes from tribes. In July 2025 three tribes sued Kalshi and Robinhood, arguing that sports prediction markets violate the Indian Gaming Regulatory Act and the exclusivity California's tribal compacts grant over gaming. A federal district judge denied a preliminary injunction; one tribe later withdrew.
On September 16, 2026 the Ninth Circuit reversed. Chief Judge Murguia, with Judges McKeown and Paez, held that the two remaining tribes are likely to succeed on their IGRA claim for contracts offered on their lands, that IGRA and the Commodity Exchange Act can be read together, and that the federal online-gambling statute (UIGEA) doesn't shield the contracts. Kalshi won only on a side claim about false advertising. The scope is tribal lands, not the state: the district court must now weigh the remaining injunction factors, and if it issues one, Kalshi and Robinhood would have to stop offering sports contracts on those two reservations, with other tribes positioned to seek the same. It follows the same court's August 28 ruling for Nevada, so the Ninth Circuit has now gone against Kalshi twice in three weeks.
Why California is the big one
Forty million people, no sportsbooks, and a state legislature that has not moved on sports betting since the 2022 ballot defeats. Prediction markets stepped into that gap in 2025, and the volume reflects it. For users that means deep markets on California teams; for the platforms it means the tribal appeal is the most commercially important case they have outside the Supreme Court.
What to do
- You can sign up and trade on all three platforms today.
- Watch the district court on remand. An injunction would mean geofencing on tribal lands, not statewide, in the first instance. Non-sports markets aren't affected.
- Check this page's date; we update it when the ruling lands.
Sources: Ninth Circuit opinion (Sept 16, 2026) as reported by InGame, SBC Americas and Paul Hastings' crypto policy tracker; CBS Sports (Oct 13, 2026); platform availability pages.