OceanaGold : November 2023 Corporate Presentation

POSITIONED FOR GROWTH

November 2023

CARE | RESPECT | INTEGRITY

PERFORMANCE | TEAMWORK

CAUTIONARY STATEMENTS

Cautionary Notes - Information Purposes Only

The information contained in this presentation is provided by OceanaGold Corporation ("OGC") for informational purposes only and does not constitute an offer to issue or arrange to issue, or the solicitation of an offer to issue, securities of OGC or other financial products. The information contained herein is not investment or financial product advice and has been prepared without taking into account the investment objectives, financial situation or particular needs of any particular person. No representation or warranty, express or implied, is made as to the fairness, accuracy, completeness or correctness of the information, opinions and conclusion contained in this presentation, except as otherwise required by law. To the maximum extent permitted by law, none of OGC or any of its directors, officers, employees or agents accepts any liability, including, without limitation, any liability arising out of fault or negligence, for any loss arising from the use of the information contained in this presentation. Furthermore, this presentation does not constitute an offer of shares for sale in the United States or to any person that is, or is acting for the account or benefit of, any U.S. person (as defined in Regulation S under the United States Securities Act of 1933, as amended (the "Securities Act")) ("U.S. Person"), or in any other jurisdiction in which such an offer would be illegal. OGC's shares have not been and will not be registered under the Securities Act.

Cautionary Statement Concerning Forward Looking Information

This presentation contains information or statements that constitute "forward-looking" information or statements within the meaning of applicable securities laws. Any statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, forecasts, projections, objectives, assumptions or future events or performance (often, but not always, using words or phrases such as "expects" or "does not expect", "is expected", "anticipates" or "does not anticipate", "plans", "estimates" or "intends", or stating that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved) are not statements of historical fact and may be forward-looking statements. Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ materially from those expressed in the forward-looking statements and information. They include, among others, the accuracy of mineral reserve and resource estimates and related assumptions, inherent operating risks, and those risk factors identified in OGC's most recent annual information forms prepared and filed with securities regulators which are available on SEDAR at www.sedar.com under OGC's profile.

With respect to forward-looking statements or information in this presentation, in making such statements or providing such information OGC has made assumptions regarding, among other things: (i) the accuracy of the estimation of mineral resources and mineral reserves; (ii) that exploration activities and studies will provide results that support anticipated development and extraction activities; (iii) that studies of estimated mine life and production rates at its mineral projects will provide results that support anticipated development and extraction activities; (iv) the accuracy of capital and operating cost estimates made in respect of OGC's mines and development projects; (v) that OGC will be able to obtain additional financing on satisfactory terms, including financing necessary to advance the development of its projects;

1. that infrastructure anticipated to be developed or operated by third parties, will be developed and/or operated as currently anticipated; (vii) that laws, rules and regulations are fairly and impartially observed and enforced; (viii) that the market prices for gold remain at levels that justify development and/or operation of any mineral project; (ix) that OGC will be able to obtain, maintain, renew or extend required permits and licenses; (x) that various environmental and social regulations and requirements do not impact OGC's exploration activities or development plans; and (xi) that key personnel will continue their employment with OGC.

All references to Mineral Reserves and Mineral Resources in this presentation are calculated in accordance with the standards set by the Canadian Institute of Mining, Metallurgy and Petroleum. Actual recoveries of mineral products may differ from Mineral Reserves and Mineral Resources as reported due to inherent uncertainties in acceptable estimating techniques. In particular, "Indicated" and "Inferred" Mineral Resources have a great amount of uncertainty as to their existence and economic and legal feasibility. It cannot be assumed that all or any part of an "Indicated" or "Inferred" Mineral Resource will ever be upgraded to a higher category of resource. Readers are cautioned not to assume that all or any part of the mineral deposits in these categories will ever be converted into Proven or Probable Reserves. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. The accuracy of any such estimates is a function of the quantity and quality of available data, and of the assumptions made and judgments used in engineering and geological interpretation, the anticipated tonnages and grades that will be mined and the estimated level of recovery that will be realized, which may prove to be unreliable and depend, to a certain extent, upon the analysis of drilling results and statistical inferences that may ultimately prove to be inaccurate. Mineral Resource estimates may have to be re-estimated based on: (i) fluctuations in the price of gold or other mineral prices; (ii) results of drilling; (iii) metallurgical testing and other studies; (iv) proposed mining operations, including dilution; (v) the evaluation of mine plans subsequent to the date of any estimates; and (vi) the possible failure to receive required permits, approvals and licences.

General Presentation Notes

All AISC and cash costs are net of by-product credits unless otherwise stated.

All financials are denominated in US Dollars unless otherwise stated.

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FOCUSED ON DELIVERING SHAREHOLDER VALUE

A global intermediate gold producer with a strong near-term growth profile

TSX: OGC	SHARES OUTSTANDING1: 707M	MARKET CAPITALISATION2: C$1.7B	NET DEBT3: $172M
Operate safely and responsibly	2023 GUIDANCE4
460,000 - 480,000 ounces gold	12,000 - 14,000 tonnes copper
		Cash Costs: $850 - $950 per ounce	AISC: $1,550 - $1,650 per ounce

Deliver on guidance

Optimize operations and maximize FCF

Execute on organic growth opportunities

DIDIPIO

Gold, Copper & Silver

HAILE

Gold & Silver

Increase returns to shareholders

1. As at September 30, 2023.
2. As at October 31, 2023.
3. As at September 30, 2023, inclusive of equipment leases.
4. Refer to October 25, 2023, Q3 MD&A for more information.

WAIHI

Gold & Silver

MACRAES

Gold

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OUR PURPOSE

Mining gold for a better future

The gold, copper and silver we produce help power the global economy; hold important historic and cultural significance; and are essential to the renewable energy and transport sectors, lifesaving medical devices and the technology that connects communities around the world

Environment

• Goal of Net Zero greenhouse gas emissions by 2050
• Pursuing decarbonization of the electricity supply by negotiating with our providers
• Demonstrating ability to decarbonize mobile equipment at Macraes
• Carbon reduction targets included in Management short term incentives

Social

• Increasing local procurement at all operations
• Formalized four funding mechanisms for local communities at Didipio
• Conformance with the World Gold
  Council's Conflict-Free Gold Standard at Didipio
• Third annual Modern Slavery Statement released

Governance

• Independently assured as being in compliance with the World Gold
  Council's Responsible Gold Mining
  Principles
• Executive KPIs aligned with shareholder interests
• Overwhelmingly independent Board, fully independent committees
• 38% female representation on Board

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OUR VISION & VALUES

Vision: To be a company people trust, want to work for & partner with, supply & invest in, to create value

We care for the safety, health and well-being of our people, the environment and local communities

We respect and listen to each other, embracing different views and diversity in all its forms

We do the right thing and take accountability to deliver on our commitments

We strive for excellence through learning, continuous improvement and innovating

We achieve great outcomes by everyone contributing and working together

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OUR STRATEGY

To increase and sustain a higher value for OceanaGold shares

STRATEGIES:		Safely & responsibly
	deliver gold production
TACTICS:	• Sustainability
	-	Health & safety
	• Operating excellence
	• Value capture programs:
	-	Asset management
	-	Procurement
	-	Continuous
		improvement

MEASURES: • TRIFR and injury severity

• Responsible Gold Mining Principles
• Financial performance
• Operating performance

A caring, inclusive and

winning culture

• Living the Vision and Values
• Capable and well led people

• Surveys
• Retention & development

Increase resources and	Financial strength	A premium rating with the
reserves cost effectively	and returns	investment community

• Exploration	• Capital management	• Independent Board
• Project execution	discipline	• Trusted Management
• Early stage entry	• Strong balance sheet	• Market engagement
• External opportunities	• Low cost capital
• Technical excellence	• Shareholder returns

• R&R replacement	• Return on investment	• P/NAV
• Projects delivered on	• Capital efficiency	• TSR
budget and schedule	• Leverage ratio and cost	• ESG ratings

• Return on investment

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THREE-YEAR OUTLOOK2

Increasing production and reducing AISC per ounce, lower capex in 2024/25

	PRODUCTION AND AISC		GROWTH CAPITAL & EXPLORATION EXPENDITURES
1,550 - 1,650
	1,300 - 1,450
		1,100 - 1,250
	550 - 600	580 - 630
			85 - 105
460 - 480
12 - 14	12 - 14	12 - 14		40 - 60	40 - 60
2023E1,2	2024E 1	2025E 1	2023E 1, 2	2024E1	2025E1
Gold (000 oz)	Copper (000 t)	AISC (US$/oz)	Growth Capital and Exploration Expenditures (US$M)

1.	See 2022 Annual MD&A for further details on three-year outlook released February 21, 2023. Also, note the Cautionary Statement Concerning Forward Looking Information on slide 2 of this presentation	7
2.	Refer to October 25, 2023, Q3 MD&A for more information on updated 2023 guidance

UPCOMING CATALYSTS

Including pipeline of prospective studies1

Project	2023			2024			2025
Q4	Q1	Q2		Q3	Q4	Q1		Q2
First Stope Ore Haile UG
Haile UG Ramp Up
Haile Ledbetter Pit Ramp Up
Haile NI 43-101
Macraes NI 43-101
Didipio Scoping Study Update
Didipio PSE Listing
Didipio NI 43-101
Waihi North PFS	Dependent on drilling and other consenting requirements

Technical Report

Operational Catalyst

Other

1. Refer to October 25, 2023, Q3 MD&A for more information	8

HAILE MINES FIRST ORE FROM UNDERGROUND

Location: South Carolina, USA	Processing Type: Carbon-in-leach flotation plant
Mine Type: Open Pit and Underground	Mine Life: 2034+3	Commodities: Gold, Silver

• Q3 weakest quarter of the year due to Mill Zone underperformance and pit transition
• Production from Mill Zone complete in Q3, stripping Ledbetter phase 2 is underway
• Annual production guidance revised downward and costs upward
• First underground ore in Q3, first stope blasted and milled in October
• Horseshoe underground infill and expansion drilling continues with success

1. 12 Month Moving Average - Total Recordable Injury Frequency

2. Refer to October 25, 2023, Q3 MD&A for more information9

3. Based on NI 43-101 Technical Report Haile Gold Mine Lancaster County, South Carolina, March 30, 2022. Subject to review and change

HAILE EXPANSION UPDATE

Horseshoe underground mines first ore

Development ore stockpiled in Q31	First stope ore to mill in October
•	3,800 ore tonnes mined from 1025 and 1000 levels in Q3	•	Three stopes planned in Q4 from 1000 and 975 levels
•	390 metres of development during the month of September,	•	Full target mining rates expected by mid-2024
	increasing through the remainder of the year

50m

Horseshoe Underground plan view, 1025 level

Horseshoe Underground long section

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1. Refer to September 14, 2023 news release for further details