The short answer is no
A boa constrictor should not live with another boa constrictor. Boas are solitary animals that meet in the wild mainly to breed, and nothing about captivity changes what a cage-mate means to them: a rival for the best hiding spot, a source of low-level stress at every hour, and a genuine danger around food. The fact that two boas can sit coiled together without incident misleads many keepers — that stillness is usually tolerance under crowding, not companionship, and it can end without warning.
Competition you cannot see, and some you can
In a shared enclosure, one boa typically claims the hide at the ideal temperature while the other makes do with the cooler or more exposed spot, and the subordinate animal's feeding, shedding, and immune health quietly suffer for it. Dominance in snakes rarely looks dramatic; it looks like one animal always in the good hide and the other always somewhere else. Then there is feeding time. Boas strike at movement and scent, and two snakes in one enclosure around rodent smell is how bites, constriction accidents, and one snake attempting to swallow the same prey item — or, in the worst recorded cases, its cage-mate — happen. Responsible feeding of a shared pair would require separating them for every meal anyway, which concedes the point.
Disease travels instantly in a shared tank
Whatever one boa carries, the other is exposed to continuously: snake mites, respiratory infections, and more serious viral conditions that boas are known to harbour can pass between cage-mates long before the first animal looks ill. Quarantine, the keeper's most useful tool, becomes impossible once two snakes share water, substrate, and airspace. If one boa later needs treatment, you will also have no clean history — whose appetite dropped, whose droppings changed, whose shed went badly — because the enclosure's evidence belongs to both animals at once.
Size, sex, and the breeding exception
Housing a male and female together invites breeding whether or not you planned for it, and an unplanned litter of live-born boas is a serious welfare commitment, not a bonus. Two males may become more restless and competitive in breeding condition, and any size mismatch adds risk to every feeding. The only accepted pairing is brief, deliberate, supervised introduction for breeding by keepers prepared for offspring and for separating the animals immediately afterwards — and even then, the pair returns to solo enclosures.
Two boas, two homes, one clear record
If you keep more than one boa, give each its own enclosure with its own hides, water, and heating, and handle and feed them as the separate animals they are. Stacked or side-by-side enclosures work well for this, provided each boa has solid visual barriers and its own temperature gradient rather than a view straight into a neighbour's territory. The reward is real: individual feeding and shed records, honest health monitoring, and snakes that rest properly because nothing else is breathing in their hide. Housed separately does not have to mean organised separately, though. KinsLe's Family Sharing shares each boa's own profile and care information with the family members who help, so everyone works from the same feeding and cleaning details for every snake.