Bamboo is commonly used for building construction. This plant is widespread and abundant in the Philippines, where some areas of the country use bamboo for construction, such as the structural parts of buildings. A crucial issue in bamboo construction is the connection system, where the connection failure develops at a low level of loading associated with bamboo splitting. This study addresses the problems in a joint between bamboo connections and determines the structural strength and durability of the Philippine bamboo mortar infill joint connection. The experimental research was conducted by carefully choosing bamboo species such as Bambusa Blumeana Schultes, Dendrocalamus Merrillianus Elmer, Bambusa Vulgaris Schrad, and Dendrocalamus Asper Schulte. These were treated by soaking in seawater and mango polyphenol extract, mortar in filling, bolt, and bamboo slats, and slaving and subjecting the samples to compression and bending tests. The results show that the mechanical strength of bamboo mortar infill joint connections increases, whereas bolted–mortar infill connections are more durable when treated with bamboo compared with untreated bamboo, and significant correlations of the bamboo mechanical strength with the properties of mortar infill, bamboo slats, bolts, treatments, curing age, and bamboo mechanical properties. Furthermore, these bamboo joint mortar infill connections resolved the failures among environmentally friendly, economical, and structurally sound connections.