The annual SIGIR-AP conference is an annual ACM-sponsored international forum that promotes and disseminates information retrieval research and development within the Asia-Pacific region defined as all of Asia, Australasia, and the islands of the Pacific and Indian Oceans. The 1st, 2nd and 3rd ACM SIGIR-AP conferences were held in Beijing in November 2023, in Tokyo in December 2024, and in Xi'an in December 2025, respectively. Following their success, the 4th ACM SIGIR-AP conference (SIGIR-AP 2026) will be held in Singapore from the 13th to the 15th of December 2026. The conference welcomes variable-length contributions related to any aspect of information retrieval and access. Tutorials and workshops will be given on Day 1, and the main conference will be held on Days 2-3. SIGIR-AP 2026 will continue to be a hybrid conference, providing both in-person and remote participation options, including support for remote presentations.