The figures have typically been assumed to be of an Iron Age origin, depicting pre-Christian deities or even connected to Janus, a Roman god of beginnings, gates, transitions, time, duality, doorways, passages, frames, and endings. He is usually depicted with two faces said to represent his ability to look into the past and future simultaneously. However, the Boa Island figures may have a different story. Interestingly, while many compare these figures to sculpture like the Tandragee Man (now in Armagh Cathedral), Dorothy Lowry-Corry suggested similarities between the figures on Boa Island and those of Carndonagh in Donegal.
I’m of a similar mind and lean towards these figures having a potential early medieval origin, as opposed to an Iron Age date. The Dreenan Figure has often been claimed to be a Janus idol, and it is commonly called the Janus Stone – but rather than a pagan idol, could it be similar to the stelae of Carndonagh which have different depictions on the front and back? A possible early medieval date is also supported by the fact that both figures were found on early Christian sites – surely if they were pagan idols they would not have been found in that context? Quite who the figures depict is certainly difficult to ascertain, and they don’t immediately strike me as being obvious representations of typical biblical figures, though it is possible that they depict high status secular figures, or may be an atypical depiction of a Christian figure.
The figures have been compared to other examples from Europe and further afield. Perhaps more tangibly, there are other sculptures believed to be from the Iron Age, like the previously mentioned Tandragee Man now on display in the Church of Ireland Cathedral in Armagh, or the three-faced Corleck Head from County Cavan on display in the National Museum of Ireland. In that sense, it is entirely possible that the figures on Boa Island date to the Iron Age, though it must be noted, to my knowledge neither the Corleck Head nor Tandragee Man were from securely dated contexts, and they too might be from another era than the presupposed Iron Age.
For an archaeologist, context is key, and as the original location of both of the Boa Island figures appears to have been within early Christian monastic sites, I lean towards them being of early Christian origin. We may never be certain in archaeology, you just have to balance the evidence and choose which interpretation is most likely. For that reason I believe that these figures are early medieval and not Iron Age, though we have so comparatively little from our Iron Age that I’m happy to be totally wrong on this one!