Basilan City's 2020 population is now estimated at 533,135. In 1950, the population of Basilan City was 116,297. Basilan City has grown by 74,960 since 2015, which represents a 3.08% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Basilan City, which typically includes Basilan City's population in addition to adjacent suburban areas.
| Year | Population | Growth Rate (%) | Growth |
|---|---|---|---|
| 2035 | 747,917 | 2.07% | 72,689 |
| 2030 | 675,228 | 2.17% | 68,720 |
| 2025 | 606,508 | 2.61% | 73,373 |
| 2020 | 533,135 | 3.08% | 74,960 |
| 2015 | 458,175 | 3.11% | 64,991 |
| 2010 | 393,184 | 1.68% | 31,388 |
| 2005 | 361,796 | 1.63% | 28,071 |
| 2000 | 333,725 | 2.55% | 39,507 |
| 1995 | 294,218 | 2.73% | 37,028 |
| 1990 | 257,190 | 2.73% | 32,366 |
| 1985 | 224,824 | 2.73% | 28,286 |
| 1980 | 196,538 | 2.73% | 24,740 |
| 1975 | 171,798 | 3.51% | 27,200 |
| 1970 | 144,598 | -0.64% | -4,749 |
| 1965 | 149,347 | -0.77% | -5,913 |
| 1960 | 155,260 | 2.79% | 19,928 |
| 1955 | 135,332 | 3.08% | 19,035 |
| 1950 | 116,297 | 0.00% |