Standardization of a collection and transmission architecture for tidal arrays would enable component designers to work towards a known specification, and the marine energy industry would be able to move forward from full scale device tests to building commercial arrays. This paper considers the requirements of tidal power arrays that are expected to be built in the coming years, explains the constraints imposed by the availability and costs of components, lists out all possible system architectures, and then evaluates them on the basis of levelized cost of energy (LCoE). The most attractive solution is a ±7.5 kV dc collection architecture, but only if wound field synchronous generators are used in the turbines. If cage induction or permanent magnet generators are to be used, floating collection hubs with full converters and 33 kV ac outputs are preferred. Improved architectures are possible with further research by power electronics engineers.