Information:

Different types of points are valid for different lengths of time:

• Gold Points are valid until the last day of the month 12 months after you earn them. (For example, points earned on 15 April 2016 would expire on 30 April 2017.)
• Platinum Points (all types) are valid until the last day of the month 6 months after you earn them. (For example, points earned on 15 April 2016 would expire on 31 October 2016.)

You can always check whether any points are about to expire via the "Your points" page of the My Nintendo website when signed in to your Nintendo Account.

Once your My Nintendo Points have expired, they can no longer be used. The expiry date cannot be extended.