# Diono Radian 3QXT SafePlus Convertible Car Seat: specs and price

**Price (US):** $449.99 at babycubby.com (MSRP $449.99 per babycubby.com and REBEL full price; frequently discounted to ~$225 at majors), as of 2026-06-27. A sourced, dated price of record — other retailers (incl. Amazon) may be lower. Among the 17 car seats we track it is #14 cheapest of 17; category median $349.99.
**Brand:** Diono
**Released:** 2021
**Deskmark:** Bronze Deskmark — pay-blind category standing 43/100, #12 of 18 in class (independent, computed from sourced data, never for sale).
**Price tracked since:** June 2026

## Specifications

| Spec | Value |
| --- | --- |
| Price (US) | $449.99 |
| Brand | Diono |
| Released | 2021 |
| Type | all_in_one |
| Min weight (lb) | 4 |
| Max weight (lb) | 120 |
| Height limit (in) | 57 in |
| Install | both |
| Steel frame | Yes |
| Expiration years | 10 |

## Where it stands

At $450, the Diono Radian 3QXT SafePlus Convertible Car Seat is #14 cheapest of the 17 car seats we track, where the median is $349.99. On the spec sheet, its min weight of 4 lb is the lowest of the 18, its max weight of 120 lb is the highest of the 18, and its expiration years of 10 is the highest of the 16.

## Archived price points (Internet Archive)

Prices as the source page rendered them on earlier dates, per web.archive.org. A separate record from our own tracking above — each row links to the snapshot it came from.

| Date | Price (US) | Snapshot |
| --- | --- | --- |
| 2024-08-08 | $449.99 | https://web.archive.org/web/20240808210319/https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat |
| 2024-12-14 | $449.99 | https://web.archive.org/web/20241214202651/https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat |
| 2025-02-15 | $449.99 | https://web.archive.org/web/20250215094227/https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat |
| 2025-06-22 | $449.99 | https://web.archive.org/web/20250622091016/https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat |
| 2025-09-06 | $449.99 | https://web.archive.org/web/20250906170823/https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat |

## What reviewers say

One whitelisted tester, Wirecutter, hands-on tested the exact Diono Radian 3QXT SafePlus (guide updated Jan 30, 2026), discussing it in the guide's 'The competition' section under all-in-one seats rather than as a pick. It's positioned as a narrow, three-across seat favored for extended rear-facing (low sides, deep recline, 50-lb rear-facing limit), but Wirecutter found it harder to install than rivals, with extra pieces to remember and an anti-rebound bar that wasn't fully flush. (Based on 1 review, 1 lab-tested, 2026-01-30.)

Praised: Narrow profile designed to fit three across in a back seat; Supports extended rear-facing — low sides, deep recline, 50-lb rear-facing limit.
Flagged: Harder to install than other convertible seats Wirecutter tested; Extra pieces you must remember to attach (rear-facing base, SafeStop tether); Anti-rebound bar not fully flush to the seat — potential safety issue if feet tuck under it.
Disagreement: Only one whitelisted tester (Wirecutter) reviewed this exact model, and it appeared in the guide's 'The competition' section (not a pick), so no cross-source comparison is possible.
Sources: Wirecutter (2026-01-30, nytimes.com)

## Frequently asked questions

**What do reviewers say about the Diono Radian 3QXT SafePlus Convertible Car Seat?**

One whitelisted tester, Wirecutter, hands-on tested the exact Diono Radian 3QXT SafePlus (guide updated Jan 30, 2026), discussing it in the guide's 'The competition' section under all-in-one seats rather than as a pick. It's positioned as a narrow, three-across seat favored for extended rear-facing (low sides, deep recline, 50-lb rear-facing limit), but Wirecutter found it harder to install than rivals, with extra pieces to remember and an anti-rebound bar that wasn't fully flush. Praised: Narrow profile designed to fit three across in a back seat; Supports extended rear-facing — low sides, deep recline, 50-lb rear-facing limit. Flagged: Harder to install than other convertible seats Wirecutter tested; Extra pieces you must remember to attach (rear-facing base, SafeStop tether); Anti-rebound bar not fully flush to the seat — potential safety issue if feet tuck under it. (From 1 tester review, 1 lab-tested.)

**How much does the Diono Radian 3QXT SafePlus Convertible Car Seat cost?**

The Diono Radian 3QXT SafePlus Convertible Car Seat has a US price of $449.99 (MSRP $449.99 per babycubby.com and REBEL full price; frequently discounted to ~$225 at majors), as of 2026-06-19.

**How does the Diono Radian 3QXT SafePlus Convertible Car Seat compare on price?**

At $450, the Diono Radian 3QXT SafePlus Convertible Car Seat is #14 cheapest of the 17 car seats we track, where the median is $349.99.

**Has the Diono Radian 3QXT SafePlus Convertible Car Seat's price changed?**

No — the Diono Radian 3QXT SafePlus Convertible Car Seat has held at $449.99 since 2024-08-08.

**What is the lowest price the Diono Radian 3QXT SafePlus Convertible Car Seat has been?**

The lowest we have recorded for the Diono Radian 3QXT SafePlus Convertible Car Seat is $449.99 on 2024-08-08.

**Is now a good time to buy the Diono Radian 3QXT SafePlus Convertible Car Seat?**

The Diono Radian 3QXT SafePlus Convertible Car Seat is currently $449.99; the lowest we have recorded is $449.99 (2024-08-08). Every price is dated, so you can judge it against its own history.

**When was the Diono Radian 3QXT SafePlus Convertible Car Seat released?**

The Diono Radian 3QXT SafePlus Convertible Car Seat was released 2021.

**What are the Diono Radian 3QXT SafePlus Convertible Car Seat's key specs?**

Diono Radian 3QXT SafePlus Convertible Car Seat (Diono): type all_in_one, min weight lb 4, max weight lb 120, height limit in 57 in, install both. Full sourced spec sheet verified 2026-06-19.

Source: https://www.babycubby.com/products/diono-radian-3qxt-safeplus-convertible-car-seat (babycubby.com, accessed 2026-06-19)
Corroboration: https://www.amazon.com/Diono-Radian-Convertible-Engineering-Protection/dp/B084Q3Z6ZK (accessed 2026-06-19)
Canonical: https://frontdeskreview.com/product/car-seats/diono-radian-3qxt/
Cite: Per The Front Desk Review, the Diono Radian 3QXT SafePlus Convertible Car Seat price of record was $449.99 as of 2026-06-19 — https://frontdeskreview.com/product/car-seats/diono-radian-3qxt/
License: CC BY 4.0. Price history: https://frontdeskreview.com/data/price-history.jsonl