The purpose of the study is to find out if the new tablet formulation oral semaglutide D is equally safe and effective as the approved oral semaglutide for treating Japanese people with type 2 diabetes. Participants will receive either oral semaglutide D (the treatment being tested) or oral semaglutide (the comparator); which treatment a participant gets is decided by chance. Oral semaglutide is an approved tablet (a treatment used as a comparator), while oral semaglutide D is described as the new tablet formulation being tested in this study. The study will last approximately 27 weeks.

Inclusion Criteria:

• Informed consent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study.
• Japanese male or female.
• Age 18 years or above at the time of signing the informed consent.
• Diagnosed with type 2 diabetes (T2D) greater than or equal to (≥) 90 days prior to day of screening.
• Glycated haemoglobin (HbA1c) of 7.0-10.5 percent (%) (53-91 millimoles per mole [mmol /mol]) (both inclusive) at screening.
• Stable daily dose(s) ≥ 60 days before screening with any 1-2 of the following oral antidiabetic drugs (OADs): Sulfonylurea (SU), glinide, thiazolidinedione (TZD), alpha-glucosidase inhibitor (α-GI), sodium-glucose cotransporter 2 (SGLT-2) inhibitor or metformin (effective or maximum tolerated dose as judged by the investigator) according to Japanese labelling.

Exclusion Criteria:

• Known or suspected hypersensitivity to study intervention(s) or related products.
• Previous participation in this study. Participation is defined as signed informed consent.
• Female who is pregnant, breast-feeding or intends to become pregnant or is of childbearing potential and not using adequate contraceptive method.
• Current participation (i.e., signed informed consent) in any other interventional clinical study.
• Exposure to an investigational medicinal product within 90 days or 5 half-lives of the investigational medicinal product (if known), whichever is longer, before screening.
• Any disorder, unwillingness or inability which in the investigator's opinion, might jeopardise the participant's safety or compliance with the protocol.
• Previous or planned (during the study period) obesity treatment with surgery or a weight loss device.
• Anticipated initiation or change in concomitant medications for more than 14 consecutive days affecting weight or glucose metabolism.
• Use of any medication with unknown or unspecified content within 90 days before screening.
• Personal or first degree relative(s) history of multiple endocrine neoplasia type 2 or medullary thyroid carcinoma.
• Presence of clinically significant gastrointestinal disorders potentially affecting absorption of drugs and/or nutrients, as judged by the investigator.
• History or presence of pancreatitis (acute or chronic).
• History of major surgical procedures involving the stomach potentially affecting absorption of study products or current presence of gastrointestinal implant.
• Myocardial infarction, stroke, transient ischaemic attack or hospitalization for unstable angina pectoris within 60 days before screening.
• Chronic heart failure classified as being in New York Heart Association (NYHA) Class IV at screening.
• Planned coronary, carotid or peripheral artery revascularisation.
• Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verified within 90 days before screening or in the period between screening and randomisation.
• Impaired liver function, defined as Alanine Aminotransferase (ALT) ≥ 2.5 times or Bilirubin >1.5 times upper normal limit at screening.
• Renal impairment with estimated glomerular filtration rate (eGFR) less than (<) 30 millilitres per minute per meter square (mL/min/1.73 m^2) as per 2021 Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI) formula (by creatinine) at screening.
• Treatment with medication for diabetes or obesity other than stated in the inclusion criteria within 90 days before screening. However, short term insulin treatment for a maximum of 14 consecutive days and prior insulin treatment for gestational diabetes are allowed.
• Presence or history of malignant neoplasms or in situ carcinomas within 5 years before screening.
• Any episodes of diabetic ketoacidosis within 90 days before screening.

According to the Novo Nordisk disclosure commitment on novonordisk-trials.com.