The European Union is about to engage in a "Green industrial deal", which emphasizes the support to industrial activities while promoting continuous energy transition to further reduce greenhouse gas emissions and energy dependency. Industrial areas where companies of various backgrounds are located, offer an unique opportunity to share both energetic and material resources and to bring energy efficiency to the highest levels. The partnership of the GreenIndustrialAreas project has therefore elaborated and tested an approach of certifying green industrial areas, aiming to highlight early adopters and to promote further energy transition in Baltic industrial areas. The approach and its criteria are documented in a Transnational standard for the certification of green industrial areas. This document is supported by a Tool-box addressed to stakeholders of Baltic industrial areas to assist different actors in industrial areas in their consideration of further energy-smart investments. Both outputs were subjected to a pilot phase during 2024 at six industrial areas in five Baltic countries, involving a large number of different public and private target groups. The project's outputs are now disseminated and proposed for wider uptake by different Baltic Sea Region actors.