What types of bonuses and penalties to a creature's land speed affect its climbing and swimming speed?

Question

This question is about creatures that don't have a special climb speed or swim speed, what is the case for most playable races.

The general rule is to make a climb/swim check and move at quarter/half your speed if the check is successful. But some bonuses to your base speed seem to be ignored.

Example :

Expeditious Retreat

This spell increases your base land speed by 30 feet. This adjustment is treated as an enhancement bonus. There is no effect on other modes of movement, such as burrow, climb, fly, or swim. As with any effect that increases your speed, this spell affects your jumping distance (see the Acrobatics skill).

There are a lot of other ways to get better land speed : alternate racial features, class features, feats and magic items. Some harmful effects from many types of attacks, including physical and magic, and the major drawback One Leg give penalties to it.

So, as a general rule, what types of bonuses and penalties to your base land speed are taken into account in the calculation of your climbing and swimming speed ?

Answer 1

The key here is "Base Speed."

You move at one quarter of your base land speed while swimming if you succeed in a swim check. Expeditious Retreat affects your base land speed, so it increases your swim speed as well.

A person who moves at 30ft/rnd succeeds their check, they typically move at 5ft/rnd. With Expeditious Retreat, your new speed is 60ft/rnd on land, and a quarter of this is 15ft/rnd.

However, spells like Haste just give you a flat increase to a chosen movement type (Or, in the case of Haste, ALL movement types,) so you would swim at 35ft/rnd.

Answer 2

I simply go with any movement type effect that doesn't specifically say it doesn't apply to the relevant movement form would extrapolate logically if there isn't a written rule.

So your one leg penalty would affect swimming and climbing a little less than land speed without crutches or likely it would be virtually identical in proportion to land speed with crutches/peg legged. If that 10 feet is 10% of the regular movement, then do the same. Round it down.

It would have virtually no effect on flying or burrowing unless the legs are involved somehow.

Expeditious retreat affects swim in our house rules because it seems to make more sense that way. It's tough to envision speeding up land speed in any way that wouldn't also speed up swimming.

Answer 3

The rules regarding swim/climb movement do not have an inherent exclusion clause regarding increases, so effects that also don't include one DO affect swim/climb.

They 'type' of a movement modifier does not determine which speeds it affects, the context (usually spell wording) does. For example, both expeditious retreat and haste are 'enhancement' bonuses but one affects swim, the other does not. Each modifier's source should be referenced to see if it modifies 'Base Speed' or a specific type of movement.

Any movement modifier that increases 'Base Speed' and lacks the exclusion clause (as your Expeditious Retreat example) alters walk/run, climb, and swim speeds; it also would affect flight or burrow that are based on 'Base Speed' (but not flight or burrow with a static speed, such as gained from various spells).

For the peg leg example, assuming 30ft speed (typical medium race), reduce your base speed to 20ft.

• A 'normal' swim check would allow you to travel 5ft (1/4 your speed) or you can take the DC increase to attempt to travel 10ft (1/2 your speed).
• If you are under the effects of expeditious retreat, you can move 50ft on land, or roll to swim 5ft or at the higher DC for 10ft.
• If you are under the effects of haste, you can move 50ft on land, or roll swim to travel 10ft (12.5 rounds down) or at the higher DC for 25ft.

I will comment that most spell effects that increase movement have the exclusion clause, unlike Haste.