A male fetus at 20 weeks of gestation presented with severe bilateral hydroureteronephrosis and distended bladder due to a large ureterocele. A percutaneous ureterocele puncture at 21 + 3 weeks aimed to decompress the ureterocele, unclog the lower urinary tract, and prevent renal damage. Post-puncture, the ureterocele decompressed, with improved left hydronephrosis and a normal right kidney. Postnatal follow-up showed bilateral HUN improvement. At term, the baby was delivered without complications, but the ureterocele refilled, necessitating a postnatal transurethral incision. This case highlights the feasibility and benefits of prenatal ureterocele puncture for fetal ureteroceles, underscoring the need for close and long-term follow-up.