According to an IIJ survey, UDP traffic reached approximately 30.6% of total traffic in 2025, significantly raising the profile of UDP, which had long been considered an exception. Against the backdrop of QUIC’s growing adoption, UDP is strengthening its potential as a TCP alternative and a new mainstay for data transmission.
TCP has long supported internet communications, while UDP was regarded as an exception. According to an IIJ survey, however, UDP’s share of traffic has increased significantly in recent years. In particular, UDP usage is said to have expanded markedly since 2020.
According to the survey, UDP accounted for 30.6% of traffic in 2025. The increase in UDP applications is believed to be a factor, while the spread of TCP alternatives such as QUIC may also have contributed.
UDP applications include communications requiring real-time performance and low latency, which have increased in recent years. QUIC’s technical characteristics may be helping to drive wider use of UDP. Attention is expected to focus on the expansion of UDP applications and the adoption of QUIC that supports them.