Mr. Graeme Jennings reports

IAMGOLD FILES UPDATED TECHNICAL REPORT FOR ESSAKANE GOLD MINE

Iamgold Corp. has filed a technical report for the company's Essakane gold mine, located in Burkina Faso. The primary objective of the technical report is to provide an updated mineral resource and mineral reserve (MRMR) estimate and an accompanying updated life-of-mine (LOM) plan for Essakane. The technical report was prepared in accordance with the disclosure requirements of National Instrument 43-101 and has an effective date of Sept. 30, 2023. The technical report is available on SEDAR+ and on the company's website.

Highlights of updated Technical Report

• Mine life extension to 2028, mining will occur from three remaining pit phases in the Essakane Main Zone ("EMZ") pit, and the Lao and Gourouol satellite pits;
• Overall production of 2.4 million ounces of gold ("oz Au") from 2023 to 2028, with an annual average gold production of approximately 400,300 oz Au during this period;
• Average estimated operating costs over the LOM (2023-2028) $32.49/t milled net of capitalized waste stripping ("CWS") (excluding CWS and stockpile movements, with CWS being transferred to sustaining capital);
• Capital expenditures over life of mine estimated at $502.7 million (including 2023);
• Mineral Reserve estimate from the open pit increased 21% to 1.9 million ounces at an average grade of 1.32 g/t
• Mineral Resource estimate from the open pit increased 37% to 3.1 million ounces at an average grade of 1.40 g/t

"As one of the top gold producing mines in West Africa, Essakane continues to be an integral part of Iamgold," commented Renaud Adams, President and Chief Executive Officer of Iamgold. "The filing of the updated Technical Report today demonstrates the successes our teams have had within the fence delineating additional ounces which have increased our mineral resource inventory and more than offset mine production depletion in 2023. As a result, we have been able to extend the mine life of Essakane an additional year, providing visibility for the next five years of operations at the project."

Life of Mine Plan

The mine life is forecast from 2023 to 2028, averaging 400,300 oz Au/year with a total production of 2.4 Moz Au over the production period. The LOM plan is based on the completion of five different mining phases:

• EMZ: three phases, Phases 5, 6, 7. Represents 87% of the gold to be mined in the LOM plan. Phase 5 is the current north phase of the EMZ pit, and the main source of ore at the Report effective date. Phase 6 is the final push back for the south part of the EMZ pit. Phase 7 is the final push back for the north part of the EMZ pit, and represents an extension of Phase 5 on the eastern wall of the EMZ pit;
• Gourouol: located to the north of the EMZ pit;
• Lao: located to the south of the EMZ pit, and accounts for 12% of the gold to be mined in the LOM plan.

The Essakane processing plant has a process rate limit of 12.19 Mtpa of hard rock equivalent. The 2024 LOM plan assumes a processing throughput capacity of 13.05 Mtpa. This is achieved by ensuring a minimum of 1.1 Mtpa of softer transition and saprolite ore will be fed to the process plant. The updated LOM plan no longer incorporates the investment, construction and operation of a heap leach facility following the successful demonstration of the capability of the plant to process a portion of the stockpiles that were designated for heap leaching through the existing facilities.

The political and security environment remains volatile in the Sahel region of Burkina Faso, particularly in the area where the mine is located. Terrorist-related incidents continue unabated in the country, the immediate region of the Essakane mine and, more broadly, the Sahel region of West Africa. Iamgold continues to take proactive measures to ensure the safety and security of in-country personnel and is constantly adjusting its protocols and the activity levels at the site according to the security environment.

About Iamgold

Iamgold is an intermediate gold producer and developer based in Canada with operating mines in North America and West Africa. The Company is building the large-scale, long life Cote Gold project in Canada in partnership with Sumitomo Metal Mining Co. Ltd., which is expected to commence production in early 2024. In addition, the Company has an established portfolio of early stage and advanced exploration projects within high potential mining districts in the Americas. Iamgold employs approximately 3,300 people and is committed to maintaining its culture of accountable mining through high standards of Environmental, Social and Governance ("ESG") practices, including its commitment to Zero Harm, in every aspect of its business. Iamgold is listed on the New York Stock Exchange (NYSE: IAG) and the Toronto Stock Exchange (TSX: IMG) and is one of the companies on the Jantzi Social Index ("JSI"), a socially screened market capitalization-weighted consisting of companies which pass a set of broadly based environmental, social and governance rating criteria.

QUALIFIED PERSON AND TECHNICAL INFORMATION

The "Technical Report on the Essakane Gold Mine, Sahel Region, Burkina Faso" that has an effective date of Sept. 30, 2023 was prepared by Mr. Francois J. Sawadogo, MAIG, Mr. Haithem Chattaoui, P.Eng., Mr. Remi Lapointe, ing, Mr. Michel Dromacque, C.Eng., Mr. Denis Doucet, ing, and Mr. Franck Napon, ing. for Iamgold Corporation. These individuals are each a Qualified Person ("QP"), as defined in NI 43-101, and have reviewed and approved the information contained in this news release that is derived from their respective sections of disclosure that is contained in the technical report.

Lisa Ragsdale, P.Geo (Director, Mining Geology, Iamgold Corporation), is the QP responsible for the review and approval of the mineral resource estimates contained herein, as at December 31, 2022. Guy Bourque, Eng. (Director, Mining, Iamgold Corporation), is the QP responsible for the review and approval of mineral reserve estimates contained herein, as at December 31, 2022.

We seek Safe Harbor.