  We report the discovery that the nearby ($\sim$ 6 pc) photometrically
variable T2.5 dwarf SIMP~J013656.5+093347 is a likely member of the $\sim$ 200
Myr-old Carina-Near moving group with a probability of $>$ 99.9% based on its
full kinematics. Our $v\sin i$ measurement of $50.9 \pm 0.8$ km s$^{-1}$
combined with the known rotation period inferred from variability measurements
provide a lower limit of $1.01 \pm 0.02$ $R_{\mathrm{Jup}}$ on the radius of
SIMP0136+0933, an independent verification that it must be younger than $\sim$
950 Myr according to evolution models. We estimate a field interloper
probability of 0.2% based on the density of field T0-T5 dwarfs. At the age of
Carina-Near, SIMP0136+0933 has an estimated mass of $12.7 \pm 1.0$
$M_{\mathrm{Jup}}$ and is predicted to have burned roughly half of its original
deuterium. SIMP0136+0933 is the closest known young moving group member to the
Sun, and is one of only a few known young T dwarfs, making it an important
benchmark for understanding the atmospheres of young planetary-mass objects.
