•Analyses the competitiveness of eight tourist regions of Northern Portugal.•Uses Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE).•Applies the Geometrical Analysis for Interactive Aid (GAIA).•Assesses the competitiveness using Tourism and Travel Competitiveness Index (TTCI).•Shows that the Porto Metropolitan Area is the leader presenting strengths in almost all indicators. The competitiveness of tourism destinations is a key issue because it enables destinations to know their position with regard to their competitors. The aim of this paper is threefold: (1) to address the measurement of the competitiveness of tourism destinations at the regional level, (2) to show the suitability of using multi-criteria techniques to measure competitiveness, and (3) to apply the PROMETHEE and GAIA methods within a competitiveness study of eight tourist destinations located in the Northern Region of Portugal. The Metropolitan Area of Porto is the first in the ranking, followed by Cávado and Douro. The results of such an analysis show the comparative strengths and weaknesses of destinations, and allow them to identify their true competitors as well as those other destinations that are most similar to them.