Company lists · Data refreshed September 2026

Top 25 Sustainability consultants based in Ireland

Name: Sustainability consultants based in Ireland
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 22, 2026 198 companies tracked

RevenueBase identified 198 sustainability consultants headquartered in Ireland as of September 2026 and tracks 3,174 professional contacts across them, including 1,297 with verified work emails. Dublin is the largest hub.

This list covers sustainability consultants headquartered in Ireland, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 22, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 22, 2026 86% judged on-target in blind review

198Companies

3,174Contacts tracked

1,297Verified emails

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The 25 largest sustainability consultants based in Ireland

Ranked by team size

Top 25 of 198 sustainability consultants based in Ireland, ranked by team size, largest first. Data refreshed Sep 22, 2026. RevenueBase Smart Search rates how each company's information relates to sustainability consultants: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Nicholas O'dwyer LTD	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	201-500	284 contacts →
	Indirect evidence “Nicholas O'Dwyer Ltd, Consulting Engineers, provide water engineering, environmental engineering and civil and structural engineering services to public and private sector clients.” Source: RevenueBase Database · checked Sep 22, 2026
2	O'connor Sutton Cronin	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	201-500	241 contacts →
	Indirect evidence “OCSC is an established International Multidisciplinary Consulting Engineering & Project Management Practice.” Source: RevenueBase Database · checked Sep 22, 2026
3	MKO	Partial evidence	Galway, IrelandHQ checked Sep 22, 2026	201-500	210 contacts →
	Partial evidence “MKO is Ireland’s largest Planning and Environmental consultancy.” Source: RevenueBase Database · checked Sep 22, 2026
4	Dbfl Consulting Engineers LTD	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	178 contacts →
	Indirect evidence “DBFL is a fully Irish-owned firm specializing in the planning, engineering design and delivery within the property, infrastructure, environmental & energy sectors.” Source: RevenueBase Database · checked Sep 22, 2026
5	Fehily Timoney And Company	Partial evidence	Cork, IrelandHQ checked Sep 22, 2026	51-200	116 contacts →
	Partial evidence “Fehily Timoney and Company is a Irish civil and environmental, engineering, scientific and planning consultancy specialising in the areas of Sustainable Infrastructure, Planning…” Source: RevenueBase Database · checked Sep 22, 2026
6	In2 Engineering	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	100 contacts →
	Indirect evidence “Engineering Firm of the Year 2025 - Engineering Excellence Awards 2025 Great Place To Work 2025-2026 accredited IN2 is a modern building services and environmental engineering…” Source: RevenueBase Database · checked Sep 22, 2026
7	Catalyst	Partial evidence	Dublin 4, IrelandHQ checked Sep 22, 2026	51-200	99 contacts →
	Partial evidence “We are a multi-disciplinary ESG, Technical Advisory and digitalisation consultancy with specialist expertise in the real estate, property and construction sectors.” Source: RevenueBase Database · checked Sep 22, 2026
8	Waterman Moylan Consulting Engineers	Partial evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	99 contacts →
	Partial evidence “Waterman Moylan is a leading engineering and environmental consultancy providing specialist services to our clients in the property, infrastructure and environment markets in…” Source: RevenueBase Database · checked Sep 22, 2026
9	20fifty Partners	Partial evidence	Limerick, IrelandHQ checked Sep 22, 2026	51-200	48 contacts →
	Partial evidence “Developing a workforce ready to meet today’s sustainability needs has never been more important.” Source: RevenueBase Database · checked Sep 22, 2026
10	Axiseng	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	11-50	47 contacts →
	Indirect evidence “Axiseng Consulting Engineers is a premier independent building services consulting engineering practice, founded in 2004 and celebrating 20 years of excellence in delivering…” Source: RevenueBase Database · checked Sep 22, 2026
11	Climeaction	Indirect evidence	Cork, IrelandHQ checked Sep 22, 2026	11-50	42 contacts →
	Indirect evidence “Climeaction Cork & Boston \| B Corp Certified \| ISO 9001 & Accredited Climeaction is an industrial decarbonisation and carbon intelligence company.” Source: RevenueBase Database · checked Sep 22, 2026
12	Erinn Innovation	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	11-50	37 contacts →
	Indirect evidence “ERINN Innovation: Guiding Impactful Research for a Sustainable Future Founded in 2017, ERINN Innovation blossomed from AquaTT UETP CLG's enduring legacy of championing research…” Source: RevenueBase Database · checked Sep 22, 2026
13	MACE	Partial evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	32 contacts →
	Partial evidence “We are a global gifting and sustainable merchandise consultancy.” Source: RevenueBase Database · checked Sep 22, 2026
14	KSN Energy	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	32 contacts →
	Indirect evidence “Complex operations made simple.” Source: RevenueBase Database · checked Sep 22, 2026
15	Lawler Sustainability	Indirect evidence	Kilkenny, IrelandHQ checked Sep 22, 2026	11-50	24 contacts →
	Indirect evidence “Helping Businesses Cut Energy Costs by up to 50% & Accelerate Their Journey to Net Zero!” Source: RevenueBase Database · checked Sep 22, 2026
16	OMC	Partial evidence	Galway, IrelandHQ checked Sep 22, 2026	11-50	22 contacts →
	Partial evidence “OMC Group, we provide a seamless, multidisciplinary consultancy service, specialising in engineering, design, and compliance solutions for commercial projects.” Source: RevenueBase Database · checked Sep 22, 2026
17	Enviroguide A DNV Company	Strong evidence	Dublin, IrelandHQ checked Sep 22, 2026	11-50	22 contacts →
	Strong evidence “Enviroguide Consulting has an established reputation for delivering environmental and sustainability consultancy services including ecology, environmental impact assessment…” Source: RevenueBase Database · checked Sep 22, 2026
18	Burke-Kennedy Doyle Architects	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	51-200	21 contacts →
	Indirect evidence “Burke-Kennedy Doyle Architects is one of Ireland’s leading architectural practices and has been a key player in the provision of innovative and professional architectural design…” Source: RevenueBase Database · checked Sep 22, 2026
19	KSN Horizon	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	11-50	21 contacts →
	Indirect evidence “Climate change, ESG requirements and the transition to a low-carbon economy are reshaping the future of real estate.” Source: RevenueBase Database · checked Sep 22, 2026
20	Aquafact	Partial evidence	Galway, IrelandHQ checked Sep 22, 2026	1-10	20 contacts →
	Partial evidence “AQUAFACT, part of APEM Group, is an environmental consultancy established in 1986.” Source: RevenueBase Database · checked Sep 22, 2026
21	Antaris Consulting	Strong evidence	Limerick, IrelandHQ checked Sep 22, 2026	11-50	20 contacts →
	Strong evidence “Founded in 1994, Antaris is an independent, Irish-owned consultancy and training firm with expertise in ISO Management Systems, Environment, Energy, Sustainability and Climate…” Source: RevenueBase Database · checked Sep 22, 2026
22	Native Events	Indirect evidence	Dublin, IrelandHQ checked Sep 22, 2026	1-10	19 contacts →
	Indirect evidence “Native Events is Ireland’s leading sustainable event production company.” Source: RevenueBase Database · checked Sep 22, 2026
23	Plan Energy	Indirect evidence	Sligo, IrelandHQ checked Sep 22, 2026	11-50	18 contacts →
	Indirect evidence “Welcome to Plan Energy, your trusted partner in decarbonisation and renewable energy.” Source: RevenueBase Database · checked Sep 22, 2026
24	Mosart	Indirect evidence	IrelandHQ checked Sep 22, 2026	11-50	17 contacts →
	Indirect evidence “Providing expert design, energy consulting & training in high performance buildings since 1993.” Source: RevenueBase Database · checked Sep 22, 2026
25	FKP Architects	Indirect evidence	Dublin 2, IrelandHQ checked Sep 22, 2026	11-50	16 contacts →
	Indirect evidence “FKP Architects is a Dublin-based firm practicing Architecture and project management.” Source: RevenueBase Database · checked Sep 22, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: sustainability consultants. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names sustainability consultants.
Partial evidence: Its own public description names part of sustainability consultants, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name sustainability consultants. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 198 sustainability consultants based in Ireland

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Sustainability consultants based in Ireland at a glance

As of Sep 22, 2026

40.9%Verified-email coverage

16.0Average contacts per company

1-10Median size (employees)

27.8%Largest-city concentration · Dublin

Sep 22, 2026Page data refreshed

Companies by employee count

1-10

138

11-50

51-200

201-500

501-1,000

Email recency for this list is measured worldwide rather than for Ireland, so it is reported there. Company counts and contact totals on this page are exact for Ireland, over 198 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among sustainability consultants, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in Ireland whose own description of what they do matches “sustainability consultants”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names sustainability consultants), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among sustainability consultants, and records with no verified work email. Companies headquartered outside Ireland are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 1,297 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 22, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Sustainability consultants by metro

Sustainability consultants in Dublin55

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names sustainability consultants, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many sustainability consultants are there based in Ireland?

RevenueBase identified 198 sustainability consultants headquartered in Ireland as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Nicholas O'dwyer LTD, headquartered in Ireland, tops this list with the largest team on record.

Which city has the most sustainability consultants?

Dublin leads with 55 headquartered companies, followed by Cork (13) and Galway (9).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 1,297 verified decision-maker contacts tracked across these 198 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 22, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.