Answer grounded in published legislation
Your question
According to namibian law is man aged 31 legal to have sex with some girlfriend aged 18 years + 6 monthes
The supplied sources do not state Namibia’s age of consent or a rule making consensual sex between a 31-year-old and an 18-year-and-6-month-old lawful or unlawful. They only show that marriage rules treat persons aged 18 and above differently from children, and may require parental, guardian, or Children’s Commissioner consent for marriage of a person under 21, not for sex. 34
Verified sources
Where this answer comes from
Combating of Immoral Practices Act 21 of 1980
“unlawful carnal intercourse” means carnal intercourse between persons who are not married or who are not partners in a customary union in terms of the traditional laws and customs applied by a particular population group referred to in section 3 of the Representative Authorities Proclamation, 1980 (Procl amation AG. 8 of 1980). [The Representative Authorities Proclamation, AG 8 of 1980, was repealed by Article 144 of the Namibian Constitution.]
Combating of Rape Act 8 of 2000
has had sexual intercourse or has performed an act of a sexual nature with another person or is the father of any child, such question shall be determined as a question of fact, and no presumption or rule of law to the effect that a boy under the age of fourteen years is incapable of sexual intercourse, shall operate. (2) The criminal capacity of an accused under the age of fourteen years who is charged with an offence of a sexual nature shall be determined in the same manner as the criminal capacity of an accused under the age of fourteen years who is charged with any other offence. Abolition of cautionary rule relating to offences of a sexual or indecent nature
Marriage Act 14 of 2024
“(2) A person may not give a child out in marriage or engagement if such child - (a) is below the age of 18; or (b) is aged 18 years or above, but does not consent to the marriage or engagement [does not consent to the marriage or engagement or is below the minimum age for marriage contemplated in Marriage Act, 1961 (Act No. 25 of 1961)].”. (b) by the substitution for the first subsection (3) of the following subsection: “(3) A - [(a) child requires the consent of the minister responsible for home affairs in order to marry; and] (b) person who has attained the age of 18 but is below the age of 21 years [also] requires the consent of his or her parent, parents or guardian or guardians or the...
Marriage Act 14 of 2024
“(2) A person may not give a child out in marriage or engagement if such child - (a) is below the age of 18; or (b) is aged 18 years or above, but does not consent to the marriage or engagement [does not consent to the marriage or engagement or is below the minimum age for marriage contemplated in Marriage Act, 1961 (Act No. 25 of 1961)].”. (b) by the substitution for the first subsection (3) of the following subsection: “(3) A - [(a) child requires the consent of the minister responsible for home affairs in order to marry; and] (b) person who has attained the age of 18 but is below the age of 21 years [also] requires the consent of his or her parent, parents or guardian or guardians or the...
Marriage Act 14 of 2024
(1) A marriage between a Namibian citizen and a foreign national who is not a permanent resident of Namibia is not in good faith and not valid for the purposes of domicile, residence or citizenship in Namibia if the Minister concludes, after an investigation as provided for in this Act, that the marriage was entered into primarily for the purpose of the foreign national acquiring Namibian domicile, residence or citizenship, even if the marriage meets all the other requirements of this Act. (2) The Minister must prescribe criteria which may be used to determine the good faith of a marriage under subsection (1). (3) The Minister must cause an investigation to be carried out according to the pr...
Marriage Act 14 of 2024
(1) A marriage between a Namibian citizen and a foreign national who is not a permanent resident of Namibia is not in good faith and not valid for the purposes of domicile, residence or citizenship in Namibia if the Minister concludes, after an investigation as provided for in this Act, that the marriage was entered into primarily for the purpose of the foreign national acquiring Namibian domicile, residence or citizenship, even if the marriage meets all the other requirements of this Act. (2) The Minister must prescribe criteria which may be used to determine the good faith of a marriage under subsection (1). (3) The Minister must cause an investigation to be carried out according to the pr...