3i Group plc head office mailing address
To mail a letter to 3i Group plc, a private equity and infrastructure investment company, send it to the company's head office at 3i Group plc, 1 Knightsbridge, London, SW1X 7LX. 3i Group is a private-equity and infrastructure investment company. This is 3i Group plc's publicly listed corporate head office — the right address for written correspondence, feedback, and formal notices. Add your return address if you'd like a reply, and confirm the address on the company's official contact page before anything time-sensitive.
3i Group plc — head office
3i Group plc 1 Knightsbridge London SW1X 7LX
Written correspondence, customer feedback, and formal notices to the company. This is the corporate head office — not a store, branch, or service centre.
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Your name
Your return address
3i Group plc1 KnightsbridgeLondon, SW1X 7LX
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Key facts
- This is 3i Group plc's corporate head office address, taken from the company's own contact page.
- 3i Group plc is a private equity and infrastructure investment company.
- Use it for letters, feedback, and formal written notices — not for parcels or in-store returns.
- Head offices relay mail internally; an attention line (e.g. "Customer Relations") helps it land in the right place.
- Include your return address and any reference number so the company can respond.
- PostPal prints your letter and mails it for you — no printer, envelope, stamps, or post office trip.
How to send your letter
- 1
Decide who your letter is for
A letter to the head office reaches the company generally. If it's for a particular team, add an attention line such as "Attention: Customer Relations" or "Office of the President" so it's routed faster.
- 2
Write your letter
Keep it clear and factual. Include any account, order, or reference number, the outcome you're looking for, and your return address so the company can write back.
- 3
Address it to the head office
First line: 3i Group plc. Then the street: 1 Knightsbridge. Then the city line: London SW1X 7LX.
- 4
Send it with PostPal
Write or upload your letter to PostPal with the address above prefilled. We print it, add your return address, and mail it for you — no printer, envelope, stamps, or trip to the post office.
Common questions
What does 3i Group plc do?
3i Group is a private-equity and infrastructure investment company. The address above is its corporate head office — the right place for written correspondence, customer feedback, and formal notices.
What is 3i Group plc's head office mailing address?
3i Group plc, 1 Knightsbridge, London, SW1X 7LX. It's the company's publicly listed corporate head office — the right address for written correspondence, feedback, and formal notices. Confirm it on 3i Group plc's official contact page before anything time-sensitive.
Will someone actually read my letter or write back?
Head offices route incoming mail to the relevant team, so a letter to the corporate address does get handled — but a personal reply isn't guaranteed. Including your return address, an account or reference number, and a clear request gives you the best chance of a response.
Is this a store or branch address?
No — this is 3i Group plc's corporate head office. For something tied to a specific location, contact that store or branch directly; use the head office for company-wide correspondence and formal notices.
Can I mail documents or a formal notice here?
Yes — you can send letters and printed documents to the head office. If you're formally serving legal documents, a company may designate a separate registered or legal address, so check its official filings first.
How do I mail 3i Group plc a letter without a printer?
Write or upload your letter to PostPal with the address prefilled. We print it, add your return address, and mail it for you — no printer, stamps, or post office trip needed.
Sources
Addresses verified August 2026 against official sources. Always confirm on the official site before time-sensitive filings.