The foldable frame for mobility aids has a mounting frame 10, a pivotal arm 20, and an operating element 30. The frame 10 has a limiting hole 11 formed adjacent a limiting end, and a through hole 12 formed between the limiting hole 11 and a second end. The pivotal arm 20 is rotatably connected to the frame 10 and has a positioning hole 21 selectively alternatively aligning with the through hole 12 and limiting hole 11. The operating element 30 is connected to the pivotal arm 20 via a ring 31 surrounding the positioning hole 21 with a pull operated securing bolt passing therethrough and selectively locking the limiting 11 or through 12 holes to prevent relative rotation. There may be a reinforcing rib 40 aligned with the frame 10. The foldable frame may be used in walkers, wheelchairs, or ladder climb assist systems to save space and aid in transport or storage.
