The current metro area population of Iwaki in 2025 is 354,000, a 0.28% decline from 2024.

• The metro area population of Iwaki in 2024 was 355,000, a 0.28% decline from 2023.
• The metro area population of Iwaki in 2023 was 356,000, a 0% increase from 2022.
• The metro area population of Iwaki in 2022 was 356,000, a 0% increase from 2021.