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For the 2026 MLB postseason and World Series, the first task is separating an event-level listing from a tradable market with final rules. Kalshi’s API can show planned event references before team outcomes appear, so traders should verify the current market page rather than infer availability, pricing, or settlement terms.
Primary sources checked: the official MLB regular-season schedule API, the Kalshi markets directory, and the CFTC designated contract market filing for Kalshi. The source snapshot was checked on August 8, 2026. The page was rechecked with the postseason in its final week: the facts below were re-verified against fresh reads of the MLB postseason schedule API and the Kalshi API between 05:31 and 05:33 UTC on October 19, 2026, and again between 05:30 and 05:45 UTC on October 25, 2026, two games into the World Series; the changes found are recorded in the update and recheck sections.
Rechecked October 25, 2026, between 05:30 and 05:45 UTC, with the World Series two games old. This section records the official results and the current Kalshi market state; it does not change the October 19 facts below.
The American League Championship Series is over: Tampa Bay closed out Cleveland 4–2 with a 7–3 win in Game 6 on Monday, October 19 at Tampa Bay. Kalshi's settlement agrees — every market in the KXMLBAL-26 event is now finalized, with Tampa Bay at yes (its market closed at 2026-10-20T03:09:16Z, minutes after the Game 6 final) and the other 14 American League markets at no.
The World Series is underway, and both opening games in Milwaukee are official finals in the MLB postseason schedule API: Game 1 on Friday, October 23 ended Brewers 3, Rays 2, and Game 2 on Saturday, October 24 ended Brewers 5, Rays 4. Milwaukee leads the series 2–0. The remaining schedule as listed by the official API: Game 3 on Monday, October 26, Game 4 on Tuesday, October 27, and Game 5 on Wednesday, October 28 — all at Tampa Bay — then Games 6 and 7, if needed, on October 30–31 at Milwaukee. Milwaukee can clinch the championship as early as October 27; Tampa Bay has to win in Tampa Bay to extend the series. No outcome beyond the two completed finals above is asserted here.
On the Kalshi side, the champion event KXMLB-26 (mutually exclusive) is down to two active markets out of 30: Milwaukee and Tampa Bay. Cleveland's market finalized no (close 2026-10-20T03:27:33Z), matching the Game 6 result. Both remaining markets keep a close_time of 2028-10-31T04:00:00Z and an expected expiration of 2026-11-01T04:00:00Z with the same early-close condition — the market "will close and expire after a title holder is declared" — so the listed close time remains a trading deadline, not a settlement date. The public API read returned no bid or ask for either market; nothing here is a price, a forecast, or a liquidity statement. The verification checklist below is unchanged.
A recheck on October 19, 2026 found the picture materially changed from the August snapshot. The MLB postseason schedule endpoint that returned no dates on August 8 now returns the full 2026 calendar: 27 dates of completed and scheduled games. The Wild Card round ran September 29 – October 1 (Atlanta over Philadelphia, the Chicago White Sox over Houston, the Yankees over Boston, and San Diego over the Cubs). The Division Series ran October 3–10: Cleveland over the White Sox, the Dodgers over Atlanta, Tampa Bay over the Yankees, and Milwaukee over San Diego.
In the National League Championship Series, the Milwaukee Brewers swept the Los Angeles Dodgers 4–0 (October 11, 12, 14, and 15), making Milwaukee the National League champion. Kalshi's own settlement agrees: the KXMLBNL-26 event is no longer open, and its Milwaukee market is finalized with result yes. The American League Championship Series is still undecided: Tampa Bay leads Cleveland 3–2 after five games (Cleveland won Games 1 and 3; Tampa Bay won Games 2, 4, and 5, with Game 4 postponed from October 16 to October 17). Game 6 is Monday, October 19 at Tampa Bay, and Game 7, if needed, is Tuesday, October 20.
The World Series dates are final in the official API: Game 1 is Friday, October 23 at Milwaukee with an 8:00 p.m. ET start, Game 2 is Saturday, October 24 at Milwaukee, Games 3–5 run Monday, October 26 through Wednesday, October 28 at the American League champion's park, and Games 6–7 would be October 30–31 at Milwaukee. The API still lists the American League side as a "TB/CLE" placeholder, which independently confirms Milwaukee as the home team for Games 1, 2, 6, and 7 under the 2-3-2 format.
On the Kalshi side, the October 19 recheck found the champion event KXMLB-26 open with 30 markets, of which exactly three remain active — Milwaukee, Cleveland, and Tampa Bay — and 27 are finalized. The American League champion event KXMLBAL-26 is open with two active markets (Cleveland and Tampa Bay). Every active market lists a close_time of 2028-10-31T04:00:00Z and an expected_expiration_time of 2026-11-01T04:00:00Z, with an early-close condition stating the market "will close and expire after a title holder is declared" — the close_time is a trading deadline, not a settlement date. The playoff-qualifier series no longer has an open event. Nothing below about verification practice changes; the bracket facts do.
The official MLB schedule API returns September 27, 2026, as the final regular-season date, with 15 games scheduled. A query covering September 28 through October 10 returns no regular-season games. That supports the conclusion that the regular season is scheduled to finish on September 27.
The exact postseason calendar was unresolved when this guide was published. MLB’s 2026 postseason schedule endpoint returned no dates at the August 8 check, so an early October postseason start and a late October World Series opener were projections, not confirmed dates. That question is now closed: the October 19 recheck found the endpoint returning the full calendar, from the September 29 Wild Card openers through a potential World Series Game 7 on October 31, as recorded in the recheck section above. Official dates still come from MLB’s postseason coverage, and the schedule API now agrees with it.
The established postseason structure provides useful planning context:
The tournament traditionally takes about a month and can extend into early November. None of that establishes a particular Kalshi close time, expiration date, or settlement threshold.
The August 8 API snapshot contained several relevant annual or custom series and 2026 event references. These identifiers are useful for verification, but they do not prove that a specific team contract is currently tradable.
The event-level records had not yet established team-level outcomes at publication. The October 19 recheck found that picture largely settled: KXMLB-26 remains open with three active markets (Milwaukee, Cleveland, Tampa Bay) and 27 finalized; KXMLBAL-26 is open with two active markets (Cleveland, Tampa Bay); and KXMLBNL-26 is closed with all 15 markets finalized, Milwaukee at yes. Current availability and prices must still come directly from Kalshi. Do not construct ticker URLs or assume that every named series has an open order book.
The metadata identifies MLB as the settlement source for the playoff-qualifier series. The October 19 recheck of the championship event KXMLB-26 lists AP, Fox Sports, ESPN, and the Governing League (MLB) as settlement sources. Traders still need to read the exact market rules because event metadata alone may not answer questions about wording, postponements, corrections, or publication timing.
A useful check takes only a few minutes and can prevent a trade based on the wrong date, team definition, or settlement source.
For market update links and related event coverage, readers can also follow the @Kalshi_market channel. For forward-looking baseball calendar context after the postseason, see the guide to 2027 MLB Opening Day schedule checks.
Kalshi is a CFTC-regulated designated contract market, but that status does not make sports-event contracts universally available or equivalent to sportsbook products. State-law disputes can exist, and eligibility may depend on location, account status, contract category, and current platform policies. Traders should verify access directly rather than relying on a general statement about sports markets.
Settlement risk is mainly a rules-reading problem. A championship contract, playoff-qualification contract, and league-title contract answer different questions. A team can qualify without winning its division, win a league pennant without winning the World Series, or be affected by a correction published after an initial report.
Execution risk also matters. A quoted probability does not show whether meaningful quantity is available at that price. Wide spreads, thin order books, fees, and late news can materially change the cost of entering or exiting a position.
Yes for the championship question, as of the October 25, 2026 update: KXMLB-26 was open with exactly two active markets — Milwaukee and Tampa Bay, the two World Series teams. The American League champion event KXMLBAL-26 has settled with Tampa Bay at yes, the National League champion event KXMLBNL-26 settled with Milwaukee at yes, and the playoff-qualifier event is closed. Availability and prices change, so verify current listings, fees, order books, and exact rules through Kalshi’s markets directory before making a trading decision.
It already started: the Wild Card round opened September 29, 2026, and the postseason runs through a potential World Series Game 7 on October 31. Tampa Bay won the American League pennant 4–2 over Cleveland (Game 6 on October 19), and the World Series is underway with Milwaukee leading 2–0 after official finals of 3–2 on October 23 and 5–4 on October 24, both in Milwaukee. Game 3 is Monday, October 26 at Tampa Bay. The original August 8 snapshot could not confirm these dates because MLB had not yet published its postseason calendar.
The verified identifiers are KXMLB-26 for the pro baseball champion, KXMLBPLAYOFFS-26 for playoff qualifiers, KXMLBAL-26 for the American League champion, and KXMLBNL-26 for the National League champion. As of the October 25 update, KXMLB-26 is the only open event, with exactly two active champion markets — Milwaukee and Tampa Bay; KXMLBAL-26 settled with Tampa Bay at yes, KXMLBNL-26 settled with Milwaukee at yes, and the qualifier event is closed. These are event identifiers, not proof that every team market is open — only two champion markets remained active. Use plain market titles if Kalshi does not display a verified ticker.
Open the specific market and compare its rules with the event metadata. Check the named settlement source, the definition of champion, the close time, the determination time, and provisions for postponements or corrections. The October 19 championship metadata listed AP, Fox Sports, ESPN, and the Governing League (MLB), and the remaining active markets carry an early-close condition that they "will close and expire after a title holder is declared" — with Milwaukee up 2–0, that condition can be met as early as October 27 without any listed deadline passing; the exact active market text should control the trading decision.
Primary-source block: Check Kalshi markets, the Kalshi rulebook, the CFTC designated contract market filing, and the official MLB postseason schedule API.
Not financial advice. Prediction-market trading is speculative, and you can lose money. Do your own research.