Objective: To demonstrate first-trimester ultrasound features of omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex using three-dimensional (3D) ultrasound orthogonal rendering, HDlive, HDlive silhouette, and SlowflowHD. Case description: A 34-year-old pregnant Japanese woman, G2, P1, was referred to our ultrasound clinic at 12 weeks and 6 days of gestation because of a suspected fetal extra-abdominal tumor. Two-dimensional (2D) sonography revealed an extra-abdominal tumor containing the stomach, liver, and intestines. 3D ultrasound orthogonal rendering revealed bladder exstrophy beneath the omphalocele and suspected thoracolumbar vertebral deformity. Ductus venosus blood flow velocity waveform was normal. HDlive and HDlive silhouette depicted bladder exstrophy beneath the omphalocele. HDlive silhouette revealed the stomach, liver, and intestines inside the tumor. SlowflowHD demonstrated characteristic intratumoral vascularity vascularity. OEIS complex was strongly suspected. Chromosome analysis using amniocentesis at 16 weeks and 4 days revealed a karyotype of 46, XY. Absent bladder and absent target signs were noted in the second- and third-trimester fetal ultrasound scans. Magnetic resonance imaging (MRI) in the third trimester revealed omphalocele with pubic symphysis diastasis and lower abdominal wall defect. At 38 weeks and 6 days of gestation, a cesarean section was performed, resulting in a male newborn weighing 2686 gm and with a height of 45.4 cm. Apgar scores were 7 (1 minute) and 8 (5 minutes), and umbilical artery (UA) blood pH was 7.318. OEIS complex was confirmed after birth. Conclusion: Three-dimensional (3D) ultrasound orthogonal rendering, HDlive, HDlive silhouette, and SlowflowHD may provide additional useful information about the unique characteristics of the OEIS complex in the first trimester of pregnancy.