The EU should seize the day: It should issue parts of the Recovery Instrument debt as green bonds and thereby boost that burgeoning market. But it is important to manage expectations: Issuing green bonds alone will not 'green' recovery spending. This will depend entirely on the criteria for climate-friendly spending in the legal texts governing the Recovery Instrument – and these so far lack teeth. So, there is a substantial risk that EU green bonds will set the wrong precedent now if backed by weak criteria. This would pre-empt future legislative work on the final EU green bond standard. If the criteria for climate-friendly spending are not strengthened, the Commission should scale back its ambition and should only issue green bonds for measures that fully match the criteria set out in the EU Taxonomy Regulation. This policy brief explains what green bonds are, how they would work in the context of the Recovery Instrument – and why they cannot be a substitute for robust rules on how the funds should be spent.