Tuvalu

Every person who, immediately before the date on which this Constitution took effect, was a citizen of Tuvalu by virtue of —
(a) Chapter IV (Citizenship) of the Independence Constitution; or
(b) the Citizenship Ordinance 1979, is as at that date a citizen of Tuvalu for the purposes of this Constitution; or 
(c) Part III (Citizenship) of the Constitution 1986,
is as at that date a citizen of Tuvalu for the purposes of this Constitution. (Sec. 45)

(1) Subject to subsections (3) and (4), a person born in Tuvalu on or after the date on which this Constitution took effect is a citizen of Tuvalu by birth.
(2) A person born outside Tuvalu on or after the date on which this Constitution took effect is a citizen of Tuvalu by birth if on the date of his birth either of his parents is, or would but for his death have been, a citizen of Tuvalu.
(3) Subject to subsection (5), a person does not become a citizen of Tuvalu by virtue of subsection (1) if at the time of his birth -
(a) neither of his parents was a citizen of Tuvalu; and
(b) his father had the privileges and immunities of an envoy to Tuvalu from a country with which Tuvalu had diplomatic relations.
(4) Subject to subsection (5), a person does not become a citizen of Tuvalu by virtue of subsection (1) if at the time of his birth—
(a) his father was a citizen of a country with which Tuvalu was at war; and
(b) the birth occurred in a place in Tuvalu occupied by that country.
(5) In the case of a person who was born out of wedlock, a reference in subsection (3) or (4) to his father shall be read as a reference to his mother. (Sec. 46)

(1) Subject to subsection (2), a person who, on or after the date on which this Constitution took effect, marries a person who is or becomes a citizen of Tuvalu is entitled, on making application in such manner as is prescribed by law, to be registered as a citizen of Tuvalu.
(2) The right conferred by subsection (1) may be made subject to such exceptions and qualifications as are declared by law to be in the interests of national security or public policy. (Sec. 47)

(1) An Act of Parliament may make provision —
(a) for the acquisition of citizenship of Tuvalu by persons who are not otherwise eligible to become citizens of Tuvalu by virtue of this Part; or
(b) for the renunciation by any person of his citizenship of Tuvalu; or
(c) for the maintenance of a register of citizens of Tuvalu who are also citizens or nationals of another country; or
(d) subject to subsection (2), for depriving any person of his citizenship of Tuvalu,
and generally for carrying into effect the purposes of this Part.
(2) Subsection (1)(d) does not apply to a person who —
(a) became a citizen automatically on Independence Day, by virtue of section 19 (persons who became citizens on Independence Day) of the Independence Constitution; or
(b) became a citizen by birth under —
(i) section 22 (persons born in Tuvalu after the day prior to Independence Day) of the Independence Constitution; or
(ii) section 23 (persons born outside Tuvalu after the day prior to independence Day) of the Independence Constitution; or
(iii) section 45 (citizenship by birth) of the Constitution 1986; or
(iv) section 46 (citizenship by birth) of this Constitution. (Sec. 48)