We characterize those countable Boolean inverse monoids that can be written as increasing unions of finite Boolean inverse monoids (respectively, finite fundamental Boolean inverse monoids, respectively finite simple Boolean inverse monoids). Our monoids are therefore countably infinite versions of finite Boolean inverse monoids, finite direct products of finite symmetric inverse monoids and of finite symmetric inverse monoids, respectively. We use MValgebras to characterize those Boolean inverse monoids that can be written as increasing unions of finite symmetric inverse monoids.