| Xian Dong Yan | |
| Other Name: | 仙洞巖 |
| Alt Name: | Fairy Cave, Deity's Cave |
| Photo Width: | 250px |
| Map: | Taiwan |
| Map Width: | 250px |
| Relief: | yes |
| Label: | Xian Dong Yan |
| Label Position: | top |
| Location: | Zhongshan, Keelung, Taiwan |
| Geology: | Sea cave |
Xian Dong Yan (仙洞巖), literally Immortal cave, is a natural sea cave in Zhongshan District, Keelung, Taiwan. It is a designated Cultural Landscape by the Bureau of Cultural Heritage in Taiwan. The cave was a shrine and resting place for fishermen during Qing dynasty period and was converted into a Buddhist Temple during the Japanese colonial period.