How can I contact DEISO?

You can contact DEISO by email, phone, address, messaging apps, or AI support. DEISO also provides a request-for-quotation form and office access information.

How do I submit a request for quotation to DEISO?

You can submit a request for quotation through DEISO’s dedicated inquiry page. The page provides a form for sending your request.

Where can I find directions to the DEISO office?

You can find the DEISO office map, directions, and visitor access instructions on the access map page.

What is DEISO’s email address?

DEISO’s general email address is info@dei.so. You can use it for general enquiries.

How can I contact DEISO?

You can contact DEISO through general contact details, a request for quotation, office directions, or direct email. The contact options include email, phone, address, messaging apps, and AI support.

How do I submit a request for quotation to DEISO?

You can submit a request for quotation through DEISO’s dedicated inquiry form. The page provides a link to request a quotation.

Where can I find directions to the DEISO office?

You can view the access map and directions for reaching the DEISO office. The page also includes access instructions for visitors.

What is DEISO’s email address?

DEISO’s general enquiry email address is info@dei.so. You can use it to email DEISO directly.

Contact DEISO for Expert Sustainability Solutions

Get in touch

How to reach DEISO

Five ways to get in touch, depending on what you need — general contact details, a formal request for quotation, a voice message, directions to the office, or a direct email.

Please note

DEISO is based in Tokyo, Japan, and operates from Tokyo only. We have no branches or offices in other countries. English is the official language of this website; pages in other languages are translations provided for convenience. Where a translation differs from the English text, the English version applies.

Contact information

All available contact options in one place — email, phone, address, messaging apps, and AI support.

View contact details →

Submit a request for quotation

Send a request for quotation, or contact DEISO using the dedicated form on the inquiry page.

Request a quotation →

Send us a voice message

Record your question in your own words, in any language, and leave your email. DEISO replies by email.

Record a voice message →

Access map and directions

How to reach the DEISO office, with directions and access instructions for visitors.

View the access map →

Email DEISO directly

For general enquiries, write to the DEISO inbox and a reply will follow.

Send an email →

Get Started with DEISO the Easy Way!

Go go.dei.so

Seven ways to start

Choose the entry point that fits where you are

Not every visitor knows what they need on day one. These seven onboarding paths cover the full range — from knowing exactly which service you want to starting from a question and letting AI guide you. Pick whichever fits.

1If you know what you needRecommended Find the right DEISO service Match your requirement to the right DEISO service in a few clicks. Filter by LCA, GHG, PCF, EPD, ESG, critical review, S-LCA, waste, circular economy, EIA, and more. Fastest path if you already know the scope. Good for “We need Scope 3 review and pre-submission checks before verification” or “We need an EPD prepared for EN 15804.” Open service finder → 2If you’re building internal capabilityRecommended Explore capacity building programs Match your team to the right DEISO training program — LCA, GHG accounting, PCF, EPD development, ESG reporting, environmental review, ISO 14001, and sector programs. Filter by role, level and format. Good for Teams building in-house LCA, GHG or EPD capability, and organisations aligned with workforce development priorities such as Saudi Arabia Vision 2030. Open training finder → 3If you need technical direction before engagementRecommended Free Technical Evaluation Request an initial technical evaluation for your sustainability requirement before committing to a full engagement. DEISO reviews your project need, technical context, enterprise requirement, reporting objective, and service direction to help identify the right path. Good for Enterprises, suppliers, and public sustainability teams that need technical direction before starting LCA, GHG, PCF, EPD, ESG, or sustainability operating system work. Start free evaluation → 4If you want an answer fast Use quick search Click the search icon in the page sidebar, or press Ctrl Shift Del to open the finder from anywhere on the site. Built for quick keyword lookups when you want results in seconds. Good for Anyone who already knows the term they are looking for — a standard, a service name, a training program — and wants to land on it without navigating. Open quick search → 5If you want to explore in depth Use advanced search Search across the full DEISO knowledge base — services, solutions, methodology, case studies, articles and technical resources. Best for when you want to research first, decide later. Good for Researchers, procurement teams and technical leads comparing methodology depth before opening a conversation. Open advanced search → 6If you’d rather see everything at once Browse the full site map A single index of every page and every article on the site — services, training programs, solutions, methodology, case studies and news. Filter it as you type, or read the structure top to bottom. Good for Returning visitors looking for a page they have seen before, and anyone who would rather scan the whole structure than answer filter questions. Open the site map → 7If you’d rather ask a questionAdvanced Ask Mirai AI DEISO Mirai™ AI Pro is DEISO’s AI guidance assistant. Ask a question about your sustainability need — it maps you to the right service, explains the approach, and hands off to the DEISO team when you’re ready. Try asking “What do we need to prepare for CSRD Scope 3 disclosure?” · “How do we start a product carbon footprint?” · “Which DEISO service fits an EPD project?” Ask Mirai →

Everything else you may need

Explore DEISO further

Not ready to start on a specific path? These pages give you the fuller picture — the core identity, the platform layer, past work, and how to reach the team.

Sustainability Operating Systems DEISO’s core identity — how the operating system model works and why it changes what sustainability execution looks like. Explore → All services The full catalogue of DEISO services across LCA, GHG, PCF, EPD, ESG, and adjacent sustainability execution. See services → Solutions DEISO solutions organised by industry challenge and business outcome — from decarbonisation to circular economy. See solutions → Platforms DEISO Visly, DEISO Spark, and the platform layer that supports every DEISO client engagement. See platforms → Case studies Real DEISO engagements across LCA, GHG, EPD and adjacent programs — with the outcomes clients actually cared about. Read cases → Our clients Enterprises, suppliers and public sustainability bodies DEISO has supported across regions and sectors. See clients → Company profile (PDF) DEISO’s structured company profile — for procurement, tenders and executive review. Open PDF → Contact DEISO Direct contact page with regional and departmental routing — for scoping calls, tenders and partnership discussions. Contact us →

Ready to engage

Request a quotation or send a direct enquiry

When you know the scope and are ready to move, submit a structured request — DEISO will scope the engagement to your context. Direct enquiries can also be sent to

Request a quotation → Email →