EU attempts to resolve competition law enforcement issues arising from the decentralised enforcement framework envisaged in Reg 1/2003 may be of interest to ASEAN Economic Community (AEC) on its journey towards creating a single market based on operational and effective competition rules. First, this chapter will assess, in the absence of EU wide harmonisation, the framework for the enforcement of EU competition law by NCAs generally and, then, in the UK and Ireland, in particular. It will further highlight how divergence in enforcement practice is being addressed by the Commission’s DG-Comp. Secondly, this chapter will assess the scope for divergent substantive rules and norms in terms of EU law under Art 3 of Regulation 1 with specific reference to the competition law provisions of the UK and Ireland. Perhaps the best encouragement for AEC offered by the EU story is the ECN’s success in securing voluntary convergence, throughout a region composed of diverse legal traditions and values, by means of a consensus building approach. Recent developments in the proposed Draft Directive to impose minimum harmonised enforcement toolkits for all NCAs offers a salutary lesson that the appropriate level of convergence depends on the perceived importance of uniformity and divergence in any multi-State competition law enforcement network context.