A temperate bacteriophage infecting Pseudomonas aeruginosa PAO1 was isolated from river water. Nanopore sequencing revealed that it has a circular double-stranded DNA genome of 45,617 bp, containing typical phage structural proteins and lambda-like lysogeny regulators. Putative O-antigen serotype conversion and anti-cyclic oligonucleotide-based antiphage signaling system (CBASS) defense system proteins were also identified.