A harmonized and integrated approach for monitoring and assessment of contamination, including hydrocarbon exploitation one, is required both by Marine Strategy Framework Directive (MSFD) at EU level and by the Ecosystem Approach (EcAp) program of the Barcelona Convention at Mediterranean level. A broad review of protocols of environmental impact assessment (EIA) procedures, monitoring and decommissioning of offshore platforms adopted by EU and non-EU countries along the Adriatic-Ionian seas was carried out in the framework of the Interreg offshore platforms in Adriatic-Ionian (ADRION) project HarmoNIA (Harmonization and networking for contaminant assessment in the Ionian and Adriatic Seas). The comparison of information provided by six ADRION countries and the application of a harmonized and integrated approach has highlighted specific challenges for managing offshore platform impacts emerged at ADRION level: (i) need of the same legislative level (the Offshore Protocol of Barcelona Convention is not ratified by all countries); (ii) set up of a task force of ADRION experts for discussing critical issues related to impacts of offshore platforms; (iii) harmonization, at the regional level, of EIA procedures, monitoring and decommissioning; (iv) need of an agreed and common list of recommended parameters to monitor in water, sediment and biota for the assessment of impacts due to platform installations and PFW discharges.