Salmonella is one of the major pathogenic bacteria that cause food poisoning. To elucidate the host infection mechanism of Salmonella enterica serovar Typhimurium-targeting phages, the bacteriophage SPN3UB was isolated from a chicken fecal sample. This phage belongs morphologically to the Siphoviridae family and infects the host via the O antigen of lipopolysaccharide (LPS). To further understand its infection mechanism, we completely sequenced and analyzed the genome. Here, we announce its complete genome sequence and report major findings from the genomic analysis results.