Members of parliaments play a pivotal role in transposing Multilateral Environmental Agreements (MEAs) into enforceable national law. The Barcelona Convention and its Protocols are a case in point: how can a newly elected parliamentarian be expected to instantly find their way through a myriad of legally binding provisions, including Regional Action Plans, addressing everything from chemical pollution to green shipping and sustainable consumption and production? The Parliamentarian’s guide to protecting the Mediterranean Sea and coast (the Guide) is aimed at parliamentarians serving in the Mediterranean region and in the European Parliament—the EU being a Contracting Party— and at staff supporting them in discharging their duties. The Guide offers practical entry points to the UNEP/MAP-Barcelona Convention system and includes non-prescriptive recommendations on how to leverage the core functions of parliament, notably representation, lawmaking, and oversight (IPU and UNDP 2017), and associated mechanisms to bridge gaps in compliance. The outcome sought through this publication is a higher level of compliance and enforcement at the national level around the Mediterranean Sea.