Fencing for conservation has become an important weapon in the conservation arsenal, and has led to real conservation success stories from mainland islands like Scotia Sanctuary (Australia) and Zealandia (New Zealand) to the reduced extinction risk of lions inside conservation fences. However, there are several issues that need to be addressed before conservation fencing becomes mainstream. Firstly, mainland islands are viewed dimly by conservation purists often from philosophical and economic terms but given the dearth of the original fauna at many of these sites this attitude may need to change. Secondly, mainland islands are inherently isolated and so strategies, like metapopulation management, to ensure gene flow are necessary, but not universally practiced. Thirdly, this isolation has ramifications for human access, and this can limit the use of conservation fencing in some countries (notably the UK where the Countryside Right of Way Act may prohibit the use of fences if they block human access). Fourthly, fencing is really only an appropriate conservation action for a limited number of threatening processes – particularly introduced species and human persecution. Expecting conservation fences to address threats they are not designed to mitigate will not improve conservation outcomes, and nor will confusing fences designed for conservation with those designed for other purposes. With these considerations in mind, conservation fencing can continue to yield genuine conservation benefits – at least until the scale of threat amelioration expands beyond that which can be fenced (e.g. Pest-free New Zealand).