September 2026 Competition Registration Calendar: What Opens and What Closes This Month

September 2026 Competition Registration Calendar: What Opens and What Closes This Month

September is not simply the month when the school competition season restarts. It is the point at which several very different decisions collide: some teams have only days left to enter an autumn programme, while other students are seeing a January, spring or summer competition open for the first time.

That distinction matters. A competition opening in September may leave months for preparation. A competition closing in September may require a teacher, team and payment before a student can even begin. Families who treat both dates in the same way can either rush unnecessarily or discover too late that an apparently individual opportunity had to be arranged through school.

The useful September question is not “Which competition is happening now?” It is “Which registration decision has to be made now, and who is allowed to make it?”

This roundup was checked on 2 September 2026 against current organiser pages and the verified competition records on CompeteMap. Where an organiser has confirmed only “September”, rather than a precise day, we say so. Dates described as a school purchase deadline, competition date or expected opening are not presented as universal student-registration deadlines.

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September registration at a glance

The earliest dates deserve attention first. In particular, Growing Future Assets, Bar Mock Trial and Wharton all depend on an adult school representative. A student cannot solve that administrative problem alone on the evening before the deadline.

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Registration deadlines in September

4 September — Growing Future Assets Investment Competition

Growing Future Assets Investment Competition 2026/27 is for teams of three to six girls from Scottish schools or eligible non-advanced college courses. A teacher registers the team and students then work with an investment-industry coach to research a listed company and build an investment case.

The official team-registration form closes on Friday 4 September 2026. This is not a good last-minute individual application: a school needs a Teacher Champion and a viable group. Its real value lies in the sustained process of research, written analysis and pitching, not in simulated trading by itself.

9 September — The Bar Mock Trial Competition

The Bar Mock Trial Competition closes applications on Wednesday 9 September 2026. It is open to eligible non-fee-paying schools and education providers for students aged 15–18. Teams prepare both prosecution and defence arguments for specially written criminal cases before competing in regional heats.

Parents should contact the school rather than attempt to register independently. The lead teacher takes responsibility for the application, entry fee, preparation and attendance. Students who like law but dislike improvised debate may still find the structure appealing: advocacy is constrained by evidence, procedure and assigned roles.

11 September — Wharton Global High School Investment Competition

Wharton Global High School Investment Competition 2026–27 closes at 5:00 p.m. ET on Friday 11 September 2026. Teams contain four to six students from the same high school and are registered by a teacher or educator adviser; students may not register themselves.

The competition is better understood as a strategy and communication project than as a race to make the most trades. Teams respond to a client case, use a market simulator and justify a long-term investment approach through an Investment Policy Statement and final report. Schools should complete both adviser registration and team-account creation before the deadline.

14 September — Irish Mathematical Olympiad Round 1

Irish Mathematical Olympiad Round 1 is organised in Irish second-level schools and supervised and marked by teachers. The school-registration action point is 14 September, with the 2026 Round 1 window running from 14–18 September.

This is the item most likely to be missed by a capable student who assumes Olympiad entry is personal. It is not. Students should ask their maths teacher whether the school has registered and when it intends to run the paper. Round 1 is designed to make serious problem solving available inside schools; it should not be described as a guaranteed direct qualification route to the final in every case.

15 September — Breakthrough Junior Challenge

Breakthrough Junior Challenge accepts applications until 11:59 p.m. PDT on 15 September 2026. Entrants aged 13–18 create an original video of no more than two minutes explaining a concept in physics, mathematics or life sciences.

The deadline covers the application and video, but submission is not the end of the work: entrants must also complete the required peer-to-peer review. A polished animation cannot compensate for a muddled explanation. The strongest reason to enter is that the format forces a student to decide what an audience genuinely needs in order to understand a difficult idea.

16 September — three ESU school competitions

The English-Speaking Union closes registration for three 2026–27 school competitions on Wednesday 16 September 2026:

• ESU Performing Shakespeare Competition, for ages 11–14, combines a monologue or duologue with an introductory speech explaining the interpretation.
• ESU Public Speaking Competition, for ages 13–16, gives a three-person team distinct speaker, questioner and chairperson roles.
• ESU Schools’ Mace Debating Competition, for ages 11–18, centres on structured argument, rebuttal and teamwork across a series of heats.

All three are institution-led. The choice should follow the student’s preferred mode of communication: performance and interpretation, prepared speaking and questioning, or adversarial argument. Entering all three is not automatically better; each creates a different rehearsal burden for the school.

The ESU International Public Speaking Competition should be treated differently. It is a qualification-based international programme for national or regional winners, not a universal competition that students can enter directly by a single September deadline. Families should contact their recognised national ESU or partner organisation for the relevant local selection calendar.

16 September — UKMT Senior Mathematical Challenge physical papers

For the UKMT Senior Mathematical Challenge, 16 September is the deadline for purchasing physical papers. Download-and-print purchases remain available until the competition date, 7 October 2026.

That distinction is useful for schools that think they have missed the entire event. The 2026 paper also changes the familiar format: it retains a 90-minute paper but uses 22 multiple-choice questions followed by three 000–999 numerical-answer questions. Students still enter through an authorised institution rather than registering personally.

20 September — Harvard–MIT Mathematics Tournament

HMMT Season 30 has a registration deadline of 20 September 2026 for both the November 2026 and February 2027 tournaments. Team and individual applications are possible, and the same date applies to financial-aid applications.

November and February should not be treated as interchangeable dates. The November tournament is generally the more accessible of the two, while February reaches further into Olympiad-style and proof-based work. International families also need to weigh travel and selection uncertainty before treating registration as a routine online form.

22 September — MCG and MOG school-entry warning

The Mathematical Competition for Girls and Mathematical Olympiad for Girls both take place on 22 September 2026. The date is primarily the competition date, not a separately advertised general student-registration deadline, so schools should purchase entries in advance through the UKMT competition system.

Students cannot sit both papers. MCG offers five answer-only questions in 90 minutes and permits wider school entry; MOG combines two answer-only questions with three full-solution questions over two and a half hours and uses discretionary entry. The meaningful decision is therefore not “Which title sounds stronger?” but whether the student is ready to communicate complete mathematical reasoning.

25 September — Stripe Young Scientist & Technology Exhibition

Stripe Young Scientist & Technology Exhibition 2027 requires students to register and submit their one-page proposal, entry form and project details by 5:00 p.m. on Friday 25 September 2026. Teachers then have until 28 September to complete their assessment.

The proposal stage rewards a question that can actually be investigated. A broad social concern or scientific interest is only a starting point; students need a workable method, a realistic scope and a teacher who has time to review the entry before the separate assessment deadline.

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Competitions opening for registration in September

1–2 September: the first wave

American Computer Science League opens 2026–27 team registration on 1 September. Advisers, not students, register teams across divisions serving grades 3–12. The season consists of four online contests, making it useful for a school or coding club that wants repeated problem-solving practice rather than a single event day.

International Greenwich Olympiad 2027 begins registration on 1 September for a project-based international programme covering several subject categories. Before committing, teams should examine the category rules and the distinction between online and face-to-face phases, including any later travel costs.

BPhO Challenge (Y13) becomes available to registered schools in September 2026, with an entry deadline of 12 December. It is a flexible Year 13 physics problem-solving resource rather than the main BPhO Olympiad selection paper. Schools may use it as a competition or classroom activity, so students should ask how their teacher intends to administer it. Families comparing physics routes may also find our BPhO and BAAO pathway guide useful.

Ireland’s CanSat has opened a teacher registration-of-interest form for 2026–27 and says the new cycle opens in September. Transition Year and Senior Cycle teams design, build and launch a can-sized satellite system. The early question is not whether a student can build the whole device, but whether the school can provide a supervising educator and sustain a long engineering project.

Student Enterprise Programme Ireland begins its 2026–27 programme on 1 September, with schools registering through their Local Enterprise Office. This is a sustained enterprise process with workshops, trade fairs and county progression, not a one-off business-plan submission.

Two additional engineering programmes are worth checking at the beginning of the month. STEM Racing Ireland currently links schools to live sign-up for teams designing, branding and racing miniature cars. UK CanSat Challenge also runs through a school or community-group adviser, although its public page had not yet displayed a precise 2026 registration-opening day when this guide was checked. Treat these as September school enquiries rather than promises that a particular form will remain open indefinitely.

On 2 September, the Mathematical Association of America opens registration for AMC 8, AMC 10 and AMC 12. Competition managers register institutions; students and parents in the United States and Canada do not register directly with the MAA. International participants must follow their country or region’s AMC International arrangements.

There is no need to rush AMC 8 on opening day, but schools planning AMC 10/12 should note the 30 September early-bird deadline and 15 October regular deadline. The 2027 AIME pathway has also changed substantially, so students targeting later invitation rounds should read our guide to the new AIME qualification and USA(J)MO route.

World of 8 Billion Student Video Contest 2027 also opens on 2 September. Students in grades 6–12 worldwide create a short original video connecting population growth to one of the year’s specified global topics. It permits individual entry and leaves until 3 March 2027, so September is best used for choosing a defensible angle and gathering reliable sources rather than rushing into production.

Mid-September: coding, mathematics, enterprise and chemistry

Mission Space Lab opens on 14 September 2026. Teams of two to six young people, supervised by a mentor, write a Python program that may run on an Astro Pi computer aboard the International Space Station. The long window to 22 February 2027 is useful, but only if teams use it: choosing a measurable research question and testing the program repeatedly matters more than making the proposal sound futuristic.

Math Kangaroo USA opens student registration on 15 September for the March 2027 individual competition. Families may register through an available centre, while schools can establish centres subject to organiser rules. It spans kindergarten through grade 12 and is a more accessible contest route than a proof Olympiad, though later questions still reward flexible problem solving.

Diamond Challenge 2027 opens its submission window on 16 September. Teams of two to four high-school students, supported by an adult adviser, develop either a business or social venture concept. The January deadline provides time for customer research and iteration; a slide deck assembled during the final week misses much of the educational value.

The UK Chemistry Olympiad also opens school registration on 16 September, continuing until 11 January 2027. The Royal Society of Chemistry recommends it mainly for students aged at least 16 because the written paper applies chemistry in unfamiliar contexts. Students cannot register directly. Our UK Chemistry Olympiad guide explains what the paper demands beyond ordinary recall.

The UKMT Senior Team Maths Challenge normally releases regional places through the school’s UKMT competition profile in September. Because regional places can fill, teachers should check the live profile rather than rely on an older public calendar date. The event is for teams of four and rewards communication as much as individual speed: Group, Crossnumber and Shuttle rounds require students to share partial progress effectively.

Late September: law and creative writing

The Magistrates’ Court Mock Trial Competition opens applications on Wednesday 23 September 2026 and closes on 21 October. It is for students aged 12–14 from eligible non-fee-paying schools in England, Wales and Northern Ireland. Teams prepare courtroom roles around a criminal case, making it a structured introduction to advocacy, evidence and civic understanding.

BBC 500 Words opens at 08:00 on Tuesday 29 September and closes at 21:00 on 6 November 2026. Children in the 5–7 and 8–11 categories write a story of no more than 500 words, which an adult submits on their behalf.

The generous writing window should be used for revision without turning the entry into an adult-edited product. A clear story idea, distinctive child’s voice and satisfying ending matter more than advanced vocabulary inserted during proofreading.

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Which opportunities should families prioritise?

A September opening is permission to begin planning, not a reason to enter everything. One well-supported team project can demand more time than several short papers combined.

School entry or individual entry?

Most of the urgent opportunities in this roundup require institutional action. AMC, UKMT, ACSL, BPhO, UK Chemistry Olympiad, the ESU school competitions and both Young Citizens mock trials all depend on a school, approved centre, teacher or adviser.

More direct family routes include BBC 500 Words, Breakthrough Junior Challenge, World of 8 Billion and some Math Kangaroo centres. Diamond Challenge and HMMT allow routes that are not limited to a conventional school team, but they still require careful attention to adviser, team and application rules.

👉 What to do this week: make a shortlist of no more than three opportunities, then ask who controls registration. If the answer is “the school”, contact the relevant department now and include the official link, date and expected team size.

Related competitions on CompeteMap

All competitions named above link to their current CompeteMap pages, where families can check eligibility, registration method, fees, format and official sources. For a broader comparison of the two major school maths systems, see UKMT vs AMC. Physics students deciding between general physics and astronomy can use the BPhO vs BAAO pathway guide.

Key Takeaways

• Deal first with the school-led deadlines on 4, 9, 11 and 16 September; these cannot usually be rescued by a student registering alone.
• IrMO Round 1 requires school coordination by 14 September, while Mission Space Lab opens on the same date for mentor-led teams.
• AMC registration opens on 2 September, but international students must follow their regional AMC International arrangements.
• MCG and MOG take place on 22 September; that date should not be mistaken for a general direct-entry deadline.
• Several programmes announce only a September opening or use a live school portal. Check the current organiser form before promising a place to a student.
• Choose by format and commitment, not by the number of competitions a student can list.

Sources checked

• MAA AMC registration information and AMC programme page
• ACSL registration
• BBC 500 Words official FAQ
• BPhO Challenge (Y13)
• Breakthrough Junior Challenge rules and timeline
• CanSat Ireland and UK CanSat
• Diamond Challenge 2027 timeline
• English-Speaking Union competitions and IPSC information
• Future Asset team registration
• HMMT Season 30 deadlines
• International Greenwich Olympiad 2027 calendar
• Irish Mathematical Olympiad Round 1 and Irish eligibility rules
• Math Kangaroo USA registration
• Astro Pi Mission Space Lab
• Royal Society of Chemistry UK Chemistry Olympiad
• STEM Racing Ireland
• Stripe Young Scientist & Technology Exhibition entry guide
• Student Enterprise Programme Ireland
• UKMT Senior Mathematical Challenge, MOG, MCG and STMC
• Wharton Investment Competition
• World of 8 Billion rules
• Young Citizens Bar Mock Trial and Magistrates’ Court Mock Trial dates