For 2015, the only change is that 3P now has lower anchors and a tether (this is a great change!).
This Sienna is available as a 7 or 8 seater. The 8th seat is the itsy-bitsy, nearly useless seat in 2C. 
The lower anchors in 3C are overlapped into 3D in a way that if you install a car seat in 3C with the lower anchors you will have a very small seat in 3D – and in many cases you won’t have any seat in 3D as the car seat in 3C will sit on top of the seat belt buckle for 3D. We’ve found that you can install an IMMI Go in 3C with LATCH and still leave the buckle for 3D accessible (the trick is to buckle 3D and pull the buckle as far to the driver’s side before installing the car seat in 3C) – but the available space in 3D is so small that you’ll need someone super skinny to be able to fit there. So long as you are OK giving up 3D, you may install a car seat in 3C with the lower anchors. However, you can not use the lower anchors to secure a booster in 3C as the booster will sit on top of the seat belt it needs.
This Sienna is available as a 7 or 8 seater. The 8th seat is the nearly useless itsy-bitsy seat in 2C.
The lower anchors in 3C are overlapped into 3D in a way that if you install a car seat in 3C with the lower anchors you will have a very small seat in 3D – and in many cases you won’t have any seat in 3D as the car seat in 3C will sit on top of the seat belt buckle for 3D. We’ve found that you can install an IMMI Go in 3C with LATCH and still leave the buckle for 3D accessible (the trick is to buckle 3D and pull the buckle as far to the driver’s side before installing the car seat in 3C) – but the available space in 3D is so small that you’ll need someone super skinny to be able to fit there. So long as you are OK giving up 3D, you may install a car seat in 3C with the lower anchors. However, you can not use the lower anchors to secure a booster in 3C as the booster will sit on top of the seat belt it needs.
This Sienna is available as a 7 or 8 seater (the additional seat is the 2nd row center seat). Unlike in the newer Sienna’s where the 2nd row center seat is useless, this 2nd row center seat is very useful and has both lower anchors and a tether anchor.
The lower anchors in 3C are overlapped into 3D in a way that if you install a car seat in 3C with the lower anchors you will have a very small seat in 3D – and in many cases you won’t have any seat in 3D as the car seat in 3C will sit on top of the seat belt buckle for 3D. We’ve found that you can install an IMMI Go in 3C with LATCH and still leave the buckle for 3D accessible (the trick is to buckle 3D and pull the buckle as far to the driver’s side before installing the car seat in 3C) – but the available space in 3D is so small that you’ll need someone super skinny to be able to fit there. So long as you are OK giving up 3D, you may install a car seat in 3C with the lower anchors. However, you can not use the lower anchors to secure a booster in 3C as the booster will sit on top of the seat belt it needs.
2010 Toyota Sienna 2nd row in 8-seater model
2010 Toyota Sienna 2nd row in 8-seater model
This Sienna was only available as a 7-seater. It also had one of the more bizarre arrangements for where you have lower anchors & tether anchors.
