Ireland-Banking & Financial Services analysis: This article was written by Phil Cody, partner (Structured Finance and Securitisation), Aisling Kelly, partner (Structured Finance and Securitisation), Helen Berrill, director (Stock Exchange Listings and Fund Registration), Sinéad Cantillon, senior professional support lawyer (Debt Finance) and Katherine Quirke, of counsel (Structured Finance and Securitisation), of Arthur Cox LLP. It examines the end of the transitional regime for external reviewers under Regulation (EU) 2023/2631, the EU Green Bond Regulation (the Regulation). It outlines the move to mandatory European Securities and Markets Authority (ESMA) registration and supervision, the secondary legislation supporting the new framework, the operation of the third-country regime, and the practical implications for issuers, external reviewers and investors using the European Green Bond (EuGB) label.