Tech events in London this week: one conference, three ways in (18-24 Sep 2026)
London tech events 18-24 Sep: Big Data LDN free at Olympia, a GBP 499 warm-up in Chiswick, a Databricks meetup inside the show, and a waitlisted AI night.
Big Data LDN puts 300-plus speakers into Olympia on Wednesday and charges nothing. The day before, the same organiser runs a room in Chiswick that costs GBP 499. That Wednesday evening, inside Olympia, a free Databricks meetup carries the conversation past the exhibition floor. One conference, three ways in, three very different prices — and picking between them is most of the week's work. There are 18 tech events in London on our city page between Friday 18 and Thursday 24 September, fifteen of them free.
The Big One: Big Data LDN, and the two events orbiting it
Big Data LDN 2026 opens Wednesday 23 September, 09:00, Olympia London, free — speakers from Google, AWS, TikTok and Spotify, and an expo floor where a lot of the hiring conversations actually happen. That is the layer everyone knows.
The other two are worth understanding before you book. Data Driven LDN 2026 runs Tuesday 22 September from 08:00 at the Clayton Hotel Chiswick, GBP 499 — Mike Ferguson chairing, Joe Reis hosting, Marcus du Sautoy of Oxford keynoting. It is deliberately senior and deliberately not a vendor showcase; if you are the person who signs off the data platform, that is the room, and the price is the filter. Then Databricks London @ Big Data LDN takes Wednesday 23 September, 18:00, at Olympia, free — a meetup edition timed for the end of day one, which is the cheapest way to get the conference's evening without the conference's badge queue.
The week ahead, day by day
Friday 18 — Newspeak House Welcome Dinner 2026, 18:30, Bethnal Green Road, free but invite only. Civic technologists, researchers and policy people over a long table. Read the gating note below before you plan around it.
Saturday 19 — Uncodebar 12, 10:00, Google London at 6 Pancras Square, free. codebar's annual attendee-led unconference: engineering, careers and community sessions set by the room on the day. The one Saturday this week worth getting up for.
Monday 21 — two free evenings. Modal x Pydantic London Meetup at 18:30 on how two developer-tools teams build for humans and agents alike, and Campaign Lab Autumn Hack Night at 19:00 at Newspeak House — bring a laptop, it is a working session, not a talk.
Tuesday 22 — the fullest day. Beyond Data Driven LDN: Deep Tech Founder and Investor Breakfast at 08:30 from Silicon Roundabout Ventures, free, quantum-robotics-defence-space; RITICS FEST, 09:30 at Imperial, free, two days on cyber-physical systems security; techUK's AI Adoption Coalition Forum at 13:00, free, real deployments rather than strategy decks; The state of harness engineering at 18:00, Arize AI with Google DeepMind at Google Pancras Square, free and waitlisted; and Agentic AI-MeetUp London #10 at 18:00 at Tessl, free, RSVP approved in advance.
Wednesday 23 — Big Data LDN's day, but not only. eCommerce Expo 2026 fills ExCeL from 09:30, free, 200-plus speakers on merchandising, payments and AI-assisted commerce, co-located with Technology for Marketing. In the evening, Climate Tech Time at The Conduit, 18:00, GBP 10.75.
Thursday 24 — SREday London 2026 Q3, 09:00 at Everyman Canary Wharf, free, for platform teams and anyone on call. Then EdTech Together at 18:00, Imperial Business School, GBP 5, on selling into schools and universities.
Venue corner: Newspeak House
Three of this week's eighteen events happen at the same converted hall on Bethnal Green Road — Friday's welcome dinner, Monday's Campaign Lab hack night, and on Wednesday 23 September at 18:30, James Muldoon on 'Love Machines', free, on AI as friend, lover, therapist and deathbot. Newspeak House is a five-minute walk from Shoreditch High Street and has been London's default room for the civic-tech-and-policy crowd for years. If the Big Data crowd is not your crowd, this is the other London.
Hidden gem: the IoT meetup that has outlasted three hype cycles
London Internet of Things Meetup No.157 runs Tuesday 22 September, 19:00, Dragon Hall in Covent Garden, free — three speakers, Q&A, and a convenor, Alexandra Deschamps-Sonsino, who has kept it going since 2011. A hundred and fifty-seven editions is its own kind of credential. Hardware people in London are thin on the ground and they are mostly in this room.
Who should go where
Founders — if you only have one evening, take Tuesday's Deep Tech Founder and Investor Breakfast if you are building anything physical, and Climate Tech Time at The Conduit on Wednesday if you are not. Skip the big expo floors unless you are selling.
Investors — your week is narrow. The Silicon Roundabout breakfast is the one place dealflow congregates, and it is free. Everything else this week is practitioners talking to practitioners.
Builders — Uncodebar on Saturday, harness engineering on Tuesday, SREday on Thursday, in that order of value. Big Data LDN's expo floor is worth an afternoon if you are quietly looking; the talks you can catch later.
Sales and marketing — eCommerce Expo at ExCeL is the buyer-dense room of the week, and it is free. Two days, co-located with Technology for Marketing, so the badge scan count justifies the DLR.
Worth knowing
The hottest thing on our board is already full. The state of harness engineering is the highest-scoring London event this week and it is showing waitlist, not sold out. Join it — free tech events routinely release 10-20% of places back in the final 48 hours.
Friday's dinner is invite only. The Newspeak House Welcome Dinner is listed as free, which is true, but it is not open registration. If you are not on the list, Monday's Campaign Lab night at the same address is open to anyone with a laptop.
Two Tuesday events do not publish an address. The Modal x Pydantic meetup and the Deep Tech breakfast release their venue on registration, so register early rather than diarising a blank. The Agentic AI meetup approves RSVPs manually — same advice.
Not everything with a crowd is a tech event. The Judge.me 5K Run on 23 September is deliberately not on our London page. It is a run.
Before you go
Fifteen free events out of eighteen, and the free one at Olympia is the biggest. Browse the full week at anopenroom.com/london, and if you run something we have missed, send it over — the corrections in this section come from organisers who told us first.