Let's start with the conclusion: Yes. Freedivers can get decompression sickness too. "Decompression sickness only happens to people wearing a tank" is one of the most widespread misunderstandings—you are still breathing ordinary air, and nitrogen still dissolves into your tissues.
Why are freedivers at risk as well? Because exposure adds up: if nitrogen has not cleared between two dives and you dive again, the residual nitrogen stacks up layer by layer. Many people dive dozens of times a day; even if each dive is only one or two minutes, the depth and the number of dives combined add up to a real risk. Symptoms often do not appear right away either—joint pain or itchy skin may show up hours later.
- Don't treat "no tank on my back" as a protective charm. The difference between scuba and freediving is the equipment and the way you breathe, not whether nitrogen enters your body.
- Limit the number of dives per day and the intervals between them. The problem is often not one deep dive, but too many dives in a day with too-short intervals; build depth gradually, step by step, and don't dive back to back without a break.
- Seek medical care immediately, even if symptoms seem mild. Joint pain, itchy skin or skin blotches, numbness or weakness, or dizziness can all be decompression sickness. When you see a doctor, explain how deep and how many times you dived, and ask for emergency treatment such as oxygen and, if needed, referral to a hyperbaric chamber. Do not dive again that day under any circumstances.
In short: whether you get decompression sickness depends on how you plan your dives for the day, not on whether you are wearing a tank. Arrange deep diving training under a qualified instructor and a compliant dive shop, follow the buddy system, and never dive alone.