| Consented | Project shareholder and financing sponsorDieppe - Le Tréport | Development And Sponsor Context | Éoliennes en Mer Dieppe Le Tréport project financing |
| Planned | Equal development partnerGwynt Glas | Development | Gwynt Glas |
| Planned | Proponent of the separate Ishikari City proposalIshikari Bay JRE / Sumitomo | Development | Sumitomo Hokkaido Ishikari City offshore wind proposal |
| Planned | Former strategic development partnerLiivi Lahe | Project Company And Development | Liivi Bay offshore wind farm |
| Consented | Former development partner and strategic investorNobelwind | Development | Nobelwind project company |
| Consented | Project shareholder and financing sponsorNoirmoutier | Development And Sponsor Context | Noirmoutier offshore wind farm project financing |
| Consented | Development and operating partnerNorthwester 2 | Development | Northwester 2 joint development with Parkwind |
| In Operation | Strategic offshore wind investorNorthwind | Development | Northwind and Belgian offshore wind partnership |
| Planned | Lead development partnerSaikai-Enoshima | Development | Saikai-Enoshima offshore wind project |
| In Construction | Historical principal contractorXilongchi Pumped Storage Power Station | Epc Balance Of Plant | Original station construction and supply contracts documented by JICA |
| In Operation | Non Operating Owner · 39%Belwind | Ownership | Sumitomo Corporation acquired a minority interest in Belwind in October 2014, with its acquisition announcement recording a 39.02% stake. |
| In Construction | Non Operating Owner · 29.5%Dieppe - Le Tréport | Ownership | Sumitomo Corporation owns 29.5% of the Dieppe - Le Treport offshore wind farm project company. |
| Consented | Non Operating Owner · 20.83%Five Estuaries | Ownership | Sumitomo Corporation remains a project partner in Five Estuaries, with a reported 20.83% stake. |
| Planned | Owner Developer · 33.33%Gwynt Glas | Ownership | Sumitomo holds 33.33% of Gwynt Glas alongside equal partners EDF power solutions and ESB. |
| In Operation | Non Operating Owner · 29.5%Noirmoutier | Ownership | Sumitomo Corporation holds a 29.5% stake in the Noirmoutier offshore wind farm project. |
| In Operation | Owner · 30%Northwind | Ownership | Sumitomo Corporation acquired a 30% stake in Northwind. In July 2026 it announced an agreement to sell the stake to Publiwind, subject to regulatory approval. |
| Dormant | Owner Developer · 12.5%Race Bank Extension | Ownership | Sumitomo Corporation held a 12.5% stake in the Race Bank Extension joint venture announced in October 2018. The extension did not progress to leasing rights in the 2017 extensions round. |
| Consented | Owner | Onshore grid assets | Five Estuaries · Intermediate Connection Asset |
| In Operation | Owner | Onshore grid assets | Northwind · Final Grid Connection Point |
| In Operation | OperatorSummit Wind Power Kashima Wind Power Plant | Onshore wind | Summit Wind Power Kashima Wind Power Plant |