Conduit for cable under a porch
Since this is outdoors, and a location where it shouldn't be subject to physical abuse (such as being stepped on, weed-whacked, or run over), nor will it see much if any sun, go ahead and run a UF cable under your porch.  You can either run it in the porch floor as if it were a NM cable (so, NM cable staples, bored holes through joists, or cable clips attached to masonry by whatever-means-needed), or leave it laying on the ground (it's direct burial suitable, after all).  You can even dig a trench under your porch and bury it if you so wish.